Aimathic
Login | English | Deutsch

Grade 8 math worksheets

Build your own math worksheets from 35,000+ problems for grades 3 to 12, from fractions to AP Calculus. Every problem comes with step-by-step solutions.

Pythagorean theorem problem solving

Learning goals

  • Identifies when the Pythagorean theorem applies.
  • Sets up the equation with the hypotenuse in the correct position.
  • Solves for a missing side length.
  • Uses square roots and units correctly.
  • Checks geometric reasonableness.

Click problems to add them to your worksheet.

Pythagorean theorem problem solving 1
The right triangle shown has hypotenuse \(x\). Write the Pythagorean equation you would use to find \(x\) from the labeled legs. Do not solve it.
Figure for problem 552196

Hints

- Identify which side is opposite the right angle. - Put the square of the hypotenuse on one side of the Pythagorean equation.

Solution

Since \(x\) is the hypotenuse, the required equation is \(3^2+4^2=x^2\).

Answer

\(3^2+4^2=x^2\)
Pythagorean theorem problem solving 2
A \(10\,\text{ft}\) ladder rests against a wall and reaches \(8\,\text{ft}\) up the wall. Let \(x\) be the distance from the base of the wall to the foot of the ladder. Which equation correctly models the right triangle? A. \(x^2+8^2=10^2\) B. \(x^2=8^2+10^2\)

Hints

- Decide which given length is the hypotenuse. - In the Pythagorean theorem, the hypotenuse square is the term by itself.

Solution

The ladder is the hypotenuse, so its square must equal the sum of the squares of the two legs. Therefore, equation A is correct.

Answer

A. \(x^2+8^2=10^2\)
Pythagorean theorem problem solving 3
The square built on a right triangle's hypotenuse has area \(36\,\text{cm}^2\). How long is the hypotenuse?

Hints

- Think of a square with a side length you know. How does its area relate to that length? - Only a nonnegative value makes sense for a measured length.

Solution

1. If the hypotenuse has length \(c\), the area of its square is \(c^2=36\,\text{cm}^2\). 2. Length is positive, so \(c=6\,\text{cm}\).

Answer

\(6\,\text{cm}\).
Pythagorean theorem problem solving 4
In a coordinate plane, points \(A(0, 0)\), \(B(w, 0)\), and \(C(w, h)\) form a right triangle with leg lengths \(w\) and \(h\). Use the Pythagorean theorem to analyze the hypotenuse length \(d\). a) \(w=1\) and \(h=1\) b) \(w=3\) and \(h=4\) Based on these cases, evaluate the claim: “The diagonal of a square or rectangle with integer side lengths is never rational.”

Hints

- Use the Pythagorean theorem. - When is the square root of a natural number rational? - Look for familiar integer side-length combinations in right triangles.

Solution

1. For part a, \(d=\sqrt{1^2+1^2}=\sqrt{2}\), which is irrational. 2. For part b, \(d=\sqrt{3^2+4^2}=\sqrt{25}=5\), which is rational. 3. Part b is a counterexample to the claim because a rectangle with integer side lengths \(3\) and \(4\) has rational diagonal length \(5\). Therefore, the claim is false.

Answer

a) \(d=\sqrt{2}\), which is irrational. b) \(d=5\), which is rational. The claim is false; a \(3\)-by-\(4\) rectangle has diagonal length \(5\).
Pythagorean theorem problem solving 5
Find the diagonal \(d\) of a rectangle with side lengths \(1.2\,\text{m}\) and \(3.5\,\text{m}\).

Hints

- A diagonal divides a rectangle into two right triangles. - Use the rectangle’s side lengths as the legs.

Solution

1. The side lengths and diagonal form a right triangle. 2. By the Pythagorean theorem, \(d^2=1.2^2+3.5^2=1.44+12.25=13.69\). 3. Therefore, \(d=\sqrt{13.69}=3.7\,\text{m}\).

Answer

\(d=3.7\,\text{m}\)
Pythagorean theorem problem solving 6
A square sheet of paper has side length \(20\,\text{cm}\). It is folded along a diagonal. Write a Pythagorean equation for the crease length \(d\), then find its length to the nearest tenth of a centimeter.

Hints

- The fold produces two right triangles. - Which sides meet at the square's right angle? - Find the positive square root, then round to tenths.

Solution

1. The diagonal is the hypotenuse of a right triangle with legs \(20\,\text{cm}\) and \(20\,\text{cm}\). 2. Thus \(d^2=20^2+20^2=800\). 3. Hence \(d=\sqrt{800}\,\text{cm}\approx28.3\,\text{cm}\).

Answer

\(d^2=20^2+20^2\); \(d\approx28.3\,\text{cm}\).
Pythagorean theorem problem solving 7
Solve each right-triangle problem. The legs are \(a\) and \(b\), and the hypotenuse is \(c\). a) \(a=\sqrt{13}\) and \(b=\sqrt{23}\). Find the exact value of \(c\). b) \(c=15\) and \(a=9\). Find \(b\).

Hints

- Squaring a square root returns the number under the radical. - Rearrange the Pythagorean theorem for the unknown side. - Identify the hypotenuse before substituting.

Solution

1. For part a, \(c^2=(\sqrt{13})^2+(\sqrt{23})^2=13+23=36\), so \(c=6\). 2. For part b, \(b^2=15^2-9^2=225-81=144\), so \(b=12\).

Answer

a) \(c=6\) b) \(b=12\)
Pythagorean theorem problem solving 8
A square garden has a diagonal of exactly \(20\,\text{ft}\). a) Let a side length be \(a\). Write a Pythagorean equation for the two equal legs and the diagonal. b) Solve for \(a\). Give an exact square-root expression and an approximation to the nearest hundredth of a foot.

Hints

- Both sides of the square form legs of equal length. - The diagonal is opposite the right angle. - After finding a side length, how could you check it against the diagonal?

Solution

1. A diagonal forms a right triangle with both legs equal to \(a\), so \(a^2+a^2=20^2\). 2. Thus \(2a^2=400\) and \(a^2=200\). 3. The side length is \(a=\sqrt{200}\,\text{ft}\approx14.14\,\text{ft}\).

Answer

a) \(a^2+a^2=20^2\). b) \(a=\sqrt{200}\,\text{ft}\approx14.14\,\text{ft}\).
Pythagorean theorem problem solving 9
A square traffic sign has diagonal length \(60\,\text{in.}\). Let its side length be \(a\). Without using a memorized square-diagonal formula, write the Pythagorean equation that connects \(a\) to the diagonal. Then use that equation to find the area of the sign.

Hints

- Use one of the right triangles created by the diagonal. - Keep \(a^2\) in your work; that quantity is also the square's area. - Your answer must include the side-length equation, not only the final area.

Solution

1. The diagonal forms a right triangle with legs \(a\) and \(a\), so \(a^2+a^2=60^2\). 2. Thus \(2a^2=3600\), so \(a^2=1800\). 3. The square's area is \(a^2\), so the area is \(1800\,\text{in.}^2\).

Answer

\(a^2+a^2=60^2\), so the area is \(1800\,\text{in.}^2\).
Pythagorean theorem problem solving 10
A tablet has a rectangular display that is \(8\,\text{in.}\) by \(13\,\text{in.}\). A protective sleeve is designed for tablets with display diagonals no longer than \(15\,\text{in.}\). Use a calculation to determine whether the tablet meets the sleeve's size limit. Give the diagonal to the nearest hundredth of an inch.

Hints

- Model the display diagonal as the hypotenuse of a right triangle. - Keep the squared side lengths separate before adding them. - Compare the calculated diagonal with the limit only after rounding as requested.

Solution

1. The display's diagonal is the hypotenuse of a right triangle with legs \(8\,\text{in.}\) and \(13\,\text{in.}\). 2. Thus \(d^2=8^2+13^2=64+169=233\). 3. Therefore, \(d=\sqrt{233}\,\text{in.}\approx15.26\,\text{in.}\). 4. Since \(15.26\,\text{in.}>15\,\text{in.}\), the tablet exceeds the sleeve's size limit.

Answer

No. The display diagonal is \(\sqrt{233}\,\text{in.}\approx15.26\,\text{in.}\), which is longer than \(15\,\text{in.}\).
Pythagorean theorem problem solving 11
Find the missing leg \(b\) in each right triangle. a) The hypotenuse is \(37\,\text{cm}\), and the other leg is \(12\,\text{cm}\). b) The hypotenuse is \(2.5\,\text{m}\), and the other leg is \(1.5\,\text{m}\).

Hints

- Recall the relationship among the three side lengths of a right triangle. - Identify the hypotenuse before substituting values. - Rearrange the formula when a leg, rather than the hypotenuse, is unknown.

Solution

1. For part a, \(b=\sqrt{37^2-12^2}=\sqrt{1225}=35\,\text{cm}\). 2. For part b, \(b=\sqrt{2.5^2-1.5^2}=\sqrt{4}=2\,\text{m}\).

Answer

a) \(b=35\,\text{cm}\) b) \(b=2\,\text{m}\)
Pythagorean theorem problem solving 12
The diagram shows the right-triangle end of a triangular prism. Its rectangular face along the hypotenuse extends \(8\,\text{cm}\) along the prism. Find the exact hypotenuse length and the exact area of that rectangular face. You may leave square roots unsimplified.
Figure for problem 531590

Hints

- Find the side opposite the right-angle mark. - Use the two labeled legs to determine the hypotenuse. - Could you use the exact unknown length in an area calculation without rounding it first?

Solution

1. The hypotenuse satisfies \(x^2=6^2+4^2=52\), so \(x=\sqrt{52}\,\text{cm}\). 2. The rectangular face is \(8\,\text{cm}\) long and \(\sqrt{52}\,\text{cm}\) wide. 3. Its area is \(8\sqrt{52}\,\text{cm}^2\).

Answer

Hypotenuse \(\sqrt{52}\,\text{cm}\); face area \(8\sqrt{52}\,\text{cm}^2\).
Pythagorean theorem problem solving 13
Find the missing side \(x\) of the right triangle. Give an exact square-root value and a decimal to the nearest hundredth of a centimeter.
Figure for problem 536434

Hints

- Identify the side across from the right angle. - How must that side's square relate to the other two squares? - Why might the exact answer and a rounded decimal look different?

Solution

1. The missing side is opposite the right angle, so it is the hypotenuse. 2. \(x^2=6^2+9^2=117\). 3. Thus \(x=\sqrt{117}\,\text{cm}\approx10.82\,\text{cm}\).

Answer

\(x=\sqrt{117}\,\text{cm}\approx10.82\,\text{cm}\).
Pythagorean theorem problem solving 14
One leg \(x\) of the right triangle is unknown. Find \(x\) as an exact square root and as a decimal to the nearest hundredth of a centimeter.
Figure for problem 536435

Hints

- Which side lies opposite the right-angle mark? - Does \(x\) label that side or another side? - Should the missing side be shorter or longer than the side marked \(17\,\text{cm}\)? - How can you rearrange the triangle's square relationship to isolate the unknown?

Solution

1. The hypotenuse is \(17\,\text{cm}\) and one leg is \(9\,\text{cm}\). 2. \(x^2=17^2-9^2=208\). 3. Thus \(x=\sqrt{208}\,\text{cm}\approx14.42\,\text{cm}\).

Answer

\(x=\sqrt{208}\,\text{cm}\approx14.42\,\text{cm}\).
Pythagorean theorem problem solving 15
Find the missing leg length \(x\) to the nearest tenth of a centimeter. Pay attention to the different units shown in the diagram.
Figure for problem 536436

Hints

- Express both displayed lengths in the same unit before calculating. - Which displayed side is opposite the marked right angle? - Isolate the square of the unknown side before taking a square root.

Solution

1. Convert the hypotenuse to centimeters: \(1.1\,\text{dm}=11\,\text{cm}\). 2. The right-triangle relation gives \(x^2+6^2=11^2\), so \(x^2=85\). 3. Thus \(x=\sqrt{85}\approx9.2\,\text{cm}\).

Answer

\(x\approx9.2\,\text{cm}\)
Pythagorean theorem problem solving 16
Find the hypotenuse length \(x\) in the triangle shown. Give the answer in decimeters to the nearest tenth.
Figure for problem 536438

Hints

- Put the two displayed leg lengths in the same unit. - Identify which side is opposite the marked right angle. - Keep the square-root value unrounded until the final answer.

Solution

1. Express both legs in decimeters: \(0.7\,\text{m}=7\,\text{dm}\). The legs are \(7\,\text{dm}\) and \(20\,\text{dm}\). 2. The hypotenuse satisfies \(x^2=7^2+20^2=449\). 3. Therefore, \(x=\sqrt{449}\approx21.2\,\text{dm}\).

Answer

\(x\approx21.2\,\text{dm}\)
Pythagorean theorem problem solving 17
A square has side length \(a\). Using the diagonal shown, derive an exact expression for its diagonal length \(d\) in terms of \(a\). You may leave the square root unsimplified.
Figure for problem 536455

Hints

- Think about the right triangle inside the square. - What are the two leg lengths? - Solve the squared-length equation for its positive root.

Solution

1. The diagonal and two neighboring sides form a right triangle with both legs \(a\). 2. The Pythagorean theorem gives \(d^2=a^2+a^2=2a^2\). 3. Since lengths are positive, \(d=\sqrt{2a^2}\).

Answer

\(d=\sqrt{2a^2}\).
Pythagorean theorem problem solving 18
Find the length of side \(x\) in the right triangle shown. All measurements are in centimeters. Round to the nearest hundredth.
Figure for problem 536477

Hints

- Identify the side opposite the right-angle mark. - Keep the two decimal squares separate until you add them. - Round only after taking the square root.

Solution

1. The side \(x\) is the hypotenuse, and the legs have lengths \(4.2\,\text{cm}\) and \(7.1\,\text{cm}\). 2. Thus \(x^2=4.2^2+7.1^2=17.64+50.41=68.05\). 3. Therefore, \(x=\sqrt{68.05}\,\text{cm}\approx8.25\,\text{cm}\).

Answer

\(x\approx8.25\,\text{cm}\).
Pythagorean theorem problem solving 19
Rectangle \(ABCD\) has the side lengths shown. Find the length of diagonal \(AC\), rounded to the nearest hundredth of a centimeter.
Figure for problem 536917

Hints

- A rectangle's diagonal forms a right triangle with two adjacent sides. - Use the two dimensions shown as perpendicular legs. - Round after taking the square root.

Solution

1. Two adjacent sides and diagonal \(AC\) form a right triangle. 2. Thus \(AC^2=11^2+7^2=170\). 3. Therefore, \(AC=\sqrt{170}\,\text{cm}\approx13.04\,\text{cm}\).

Answer

\(AC\approx13.04\,\text{cm}\).
Pythagorean theorem problem solving 20
A rectangle has the side and diagonal lengths shown. Find the other side, rounded to the nearest hundredth of a centimeter.
Figure for problem 536918

Hints

- Identify the hypotenuse in the rectangle's right triangle. - Which square-length equation connects the diagonal with the two sides? - Check that your result is shorter than the diagonal before rounding.

Solution

1. A rectangle's diagonal is the hypotenuse of a right triangle with the rectangle's sides as legs. 2. If the other side is \(b\), then \(b^2=19^2-7^2=312\). 3. Therefore, \(b=\sqrt{312}\,\text{cm}\approx17.66\,\text{cm}\).

Answer

\(b\approx17.66\,\text{cm}\).
Pythagorean theorem problem solving 21
A rectangular window is \(9\,\text{in.}\) wide and \(12\,\text{in.}\) tall. A brace runs straight from one corner to the opposite corner. Write an equation for its length \(d\). Do not calculate \(d\). Explain why your equation applies.

Hints

- What kind of angle do the window's two edges form? - Which part of the window would be opposite that angle in a triangle?

Solution

1. A window corner is a right angle. The width and height form the legs of a right triangle, and the diagonal brace is its hypotenuse. 2. Therefore, \(d^2=9^2+12^2\).

Answer

\(d^2=9^2+12^2\), because the diagonal crosses a right triangle formed by the window's width and height.
Pythagorean theorem problem solving 22
Find the length of \(BC\) in the right triangle. Show your Pythagorean calculation.
Figure for problem 559998

Hints

- Which side is opposite the right angle? - How are the squares of the three side lengths related? - Should the unknown length be longer or shorter than either leg?

Solution

1. The legs are \(8\,\text{cm}\) and \(15\,\text{cm}\); \(BC\) is opposite the right angle. 2. \(BC^2=8^2+15^2=64+225=289\). 3. \(BC=17\,\text{cm}\).

Answer

\(BC^2=8^2+15^2=289\), so \(BC=17\,\text{cm}\).
Pythagorean theorem problem solving 23
Find the length of leg \(AC\) in the right triangle. Explain why the squares are subtracted.
Figure for problem 559999

Hints

- Which side is opposite the right angle? - Does \(AC\) name the longest side or a shorter side? - How do the squares of both legs relate to the hypotenuse's square? - How could you check whether a proposed leg is too long?

Solution

1. \(BC=13\,\text{cm}\) is the hypotenuse and \(AB=5\,\text{cm}\) is a leg. 2. \(AC^2+5^2=13^2\), so \(AC^2=169-25=144\). 3. Therefore, \(AC=12\,\text{cm}\). Subtraction isolates the missing leg's square.

Answer

\(AC=12\,\text{cm}\); subtract the known leg's square from the hypotenuse's square.
Pythagorean theorem problem solving 24
A right triangle has legs of \(1\,\text{cm}\) each. Find its hypotenuse in exact form, then round to the nearest hundredth of a centimeter.

Hints

- Add the squares of the legs first. - An exact square root need not be a whole number. - Use the third decimal place to round to hundredths.

Solution

1. By the Pythagorean theorem, \(c^2=1^2+1^2=2\). 2. The exact length is \(\sqrt{2}\,\text{cm}\). 3. Since \(\sqrt{2}\approx1.4142\), the length rounds to \(1.41\,\text{cm}\).

Answer

Exactly \(\sqrt{2}\,\text{cm}\); approximately \(1.41\,\text{cm}\).
Pythagorean theorem problem solving 25
Aria walks \(6\,\text{m}\) east and then \(8\,\text{m}\) north. She says she is \(14\,\text{m}\) from where she started because \(6+8=14\). What does \(14\,\text{m}\) measure? How far is she from her starting point in a straight line? Show a right-triangle equation.

Hints

- Does adding the two walks give the route length or the shortest distance home? - What angle do east and north directions form? - Think about the direct path across the triangle.

Solution

1. The sum \(6+8=14\,\text{m}\) is how far Aria walked along the two streets, not her straight-line distance from the start. 2. The east and north parts meet at a right angle, making the straight path a hypotenuse. 3. Its length is \(\sqrt{6^2+8^2}=10\,\text{m}\).

Answer

\(14\,\text{m}\) is the total distance walked. The direct path satisfies \(d^2=6^2+8^2\), so its length is \(10\,\text{m}\).
Pythagorean theorem problem solving 26
A sprinkler stands at the center of a square lawn with side length \(40\,\text{ft}\). Its current spray radius is \(20\,\text{ft}\). a) Write a Pythagorean equation for the minimum radius needed to reach a corner. Give the exact square-root length and its approximation to the nearest hundredth of a foot. b) How much farther must the spray reach? Give the exact difference and an approximation to the nearest hundredth.

Hints

- Where is the farthest point of a square lawn from its center? - What simpler lengths could help you find that distance? - Why might it help to keep the exact length until after you subtract?

Solution

1. The horizontal and vertical distances from the center to a corner are both \(20\,\text{ft}\), so \(r^2=20^2+20^2=800\). 2. Therefore, \(r=\sqrt{800}\,\text{ft}\approx28.28\,\text{ft}\). 3. The extra reach is \((\sqrt{800}-20)\,\text{ft}\approx8.28\,\text{ft}\).

Answer

a) \(r^2=20^2+20^2\); \(r=\sqrt{800}\,\text{ft}\approx28.28\,\text{ft}\). b) \((\sqrt{800}-20)\,\text{ft}\approx8.28\,\text{ft}\).
Pythagorean theorem problem solving 27
A rectangular park is \(110\,\text{yd}\) wide and \(150\,\text{yd}\) long. One route goes directly from one corner to the opposite corner; another follows two sides of the park. How much shorter is the direct route? Round to the nearest tenth of a yard.

Hints

- Compare the length of the two-side route with the straight corner-to-corner route. - What right triangle is formed by the park's two side lengths and its diagonal? - Keep the diagonal unrounded until the final subtraction.

Solution

1. The route along two sides is \(110+150=260\,\text{yd}\). 2. The direct route is the rectangle's diagonal, so its length is \(\sqrt{110^2+150^2}=\sqrt{34{,}600}\approx186.0\,\text{yd}\). 3. The difference is \(260-\sqrt{34{,}600}\approx73.989\,\text{yd}\), which rounds to \(74.0\,\text{yd}\).

Answer

The direct route is \(74.0\,\text{yd}\) shorter.
Pythagorean theorem problem solving 28
A triangle has side lengths \(a=15\,\text{cm}\), \(b=20\,\text{cm}\), and \(c=24\,\text{cm}\). a) Use calculations to explain why the triangle is not a right triangle. b) Keeping \(a\) and \(b\) unchanged, find the length of \(c\) that would make a right triangle with \(c\) as the hypotenuse.

Hints

- Recall how the converse of the Pythagorean theorem relates the three side lengths. - Compare the sum of the squares of the two shorter sides with the square of the longest side. - For the right-triangle case, use \(c\) as the hypotenuse in the Pythagorean theorem.

Solution

1. The longest side is \(c=24\,\text{cm}\). Since \(15^2+20^2=625\) while \(24^2=576\), the triangle is not a right triangle. 2. For \(c\) to be the hypotenuse, \(c^2=15^2+20^2=625\). Therefore, \(c=\sqrt{625}=25\,\text{cm}\).

Answer

a) The triangle is not a right triangle because \(15^2+20^2=625\ne576=24^2\). b) \(c=25\,\text{cm}\)
Pythagorean theorem problem solving 29
Two beams are \(12\,\text{ft}\) and \(16\,\text{ft}\) long, and the measured diagonal between their endpoints is \(20.5\,\text{ft}\). a) Show that the beams do not form an exact right angle. b) Find the diagonal length required for a right angle. c) If the \(20.5\,\text{ft}\) diagonal and the \(16\,\text{ft}\) beam are kept, how long should the other beam be? Round to the nearest hundredth of a foot.

Hints

- Treat the beams as legs and the diagonal as the possible hypotenuse. - Compare the sum of the squares of the beam lengths with the square of the measured diagonal. - For part c, think about which side is unknown after the other leg and the diagonal are fixed.

Solution

1. \(12^2+16^2=400\), while \(20.5^2=420.25\). Because the values are not equal, the beams do not form a right angle. 2. For a right angle with beams \(12\,\text{ft}\) and \(16\,\text{ft}\), \(d=\sqrt{12^2+16^2}=20\,\text{ft}\). 3. Let the unknown beam length be \(a\). Then \(a^2=20.5^2-16^2=164.25\), so \(a=\sqrt{164.25}\,\text{ft}\approx12.82\,\text{ft}\).

Answer

a) The beams do not form an exact right angle because \(12^2+16^2=400\ne420.25=20.5^2\). b) \(20\,\text{ft}\) c) Approximately \(12.82\,\text{ft}\)
Pythagorean theorem problem solving 30
A rectangle has diagonal \(13\,\text{cm}\) and one side length \(6\,\text{cm}\). Find the other side length \(b\), the area \(A\), and the perimeter \(P\). Round each result to the nearest tenth where needed.

Hints

- A rectangle's diagonal and two adjacent sides form a right triangle. - Find the unknown side before using the rectangle formulas. - Keep the exact side length until the final rounding of each requested quantity.

Solution

1. The diagonal is the hypotenuse of a right triangle formed by two sides of the rectangle. Thus \(b^2=13^2-6^2=133\), so \(b=\sqrt{133}\approx11.5\,\text{cm}\). 2. The area is \(A=6\sqrt{133}\approx69.2\,\text{cm}^2\). 3. The perimeter is \(P=2(6+\sqrt{133})\approx35.1\,\text{cm}\).

Answer

\(b\approx11.5\,\text{cm}\), \(A\approx69.2\,\text{cm}^2\), and \(P\approx35.1\,\text{cm}\).
Pythagorean theorem problem solving 31
A rectangular wooden gate is \(5\,\text{ft}\) wide and has area \(35\,\text{ft}^2\). A diagonal brace will be installed from one corner to the opposite corner. How long should the brace be? Round to the nearest tenth of a foot.

Hints

- Use the gate's area and width to determine its other dimension first. - The diagonal brace and the two side lengths form a right triangle. - Round only after finding the diagonal from the exact side lengths.

Solution

1. The gate's height is \(35\div5=7\,\text{ft}\). 2. The brace is the rectangle's diagonal, so its length is \(\sqrt{5^2+7^2}=\sqrt{74}\approx8.602\,\text{ft}\). 3. Rounded to the nearest tenth, the brace should be \(8.6\,\text{ft}\) long.

Answer

The brace should be \(8.6\,\text{ft}\) long.
Pythagorean theorem problem solving 32
A flagpole is anchored at its base on a level schoolyard. A rope is attached \(4.00\,\text{m}\) along the pole from its base and fastened to a ground stake \(3.30\,\text{m}\) from the base. The tight rope measures \(5.20\,\text{m}\). Is the pole exactly perpendicular to the ground? If not, find the exact rope length it would need if upright, with the same attachment distance along the pole and the same stake position. Round that length to the nearest hundredth of a meter.

Hints

- Sketch the pole, rope, and ground as the sides of a triangle. - What would be true of those three side lengths if the base angle were \(90^\circ\)? - Compare the original triangle with one drawn for an upright pole. Which two side lengths would remain the same?

Solution

1. If the pole were upright, its first \(4.00\,\text{m}\), the \(3.30\,\text{m}\) ground distance, and the rope would form a right triangle. 2. The sum of the leg squares is \(4.00^2+3.30^2=26.89\), while the current rope square is \(5.20^2=27.04\). They differ, so the angle at the pole base is not right. 3. For an upright pole, the rope would measure \(\sqrt{26.89}\,\text{m}\approx5.19\,\text{m}\).

Answer

The pole is not perpendicular to the ground. The upright-pole rope length would be \(\sqrt{26.89}\,\text{m}\approx5.19\,\text{m}\).
Pythagorean theorem problem solving 33
Four ropes have marked segments that can be used as the side lengths of a triangular garden bed. The numbers give the segment lengths in units: Rope A: \(9, 12, 15\) Rope B: \(7, 10, 18\) Rope C: \(10, 10, 14\) Rope D: \(5, 12, 13\) a) One rope cannot form a triangle at all. Identify it and justify your answer mathematically. b) Which of the remaining ropes can form an exact right triangle? Show the calculations that support your answer.

Hints

- What condition must three lengths satisfy to form a closed triangle? - What relationship among the squared side lengths shows that a triangle is right? - Is equality in the triangle inequality enough to form a triangle? - Which side must be treated as the possible hypotenuse?

Solution

1. For Rope B, the two shorter lengths add to \(7+10=17\), which is less than \(18\). Therefore, Rope B cannot form a triangle. 2. Rope A satisfies \(9^2+12^2=225=15^2\), so it forms a right triangle. 3. Rope C gives \(10^2+10^2=200\), while \(14^2=196\), so it does not form a right triangle. 4. Rope D satisfies \(5^2+12^2=169=13^2\), so it forms a right triangle.

Answer

a) Rope B cannot form a triangle because \(7+10<18\). b) Ropes A and D form right triangles because \(9^2+12^2=15^2\) and \(5^2+12^2=13^2\).
Pythagorean theorem problem solving 34
A \(60\,\text{m}\) rope will be used at full length to mark the perimeter of a right triangle. All three side lengths, \(a\), \(b\), and \(c\), must be whole numbers of meters. Find two different sets of side lengths and show that each set forms a right triangle.

Hints

- Recall a simple whole-number triple that satisfies the Pythagorean theorem. - Scaling all three sides of a right triangle by the same factor preserves the right angle. - The three side lengths must add to exactly \(60\).

Solution

1. A scaled \((3, 4, 5)\) triangle can have perimeter \(60\,\text{m}\). Since \(3+4+5=12\) and \(60\div12=5\), scaling each side by \(5\) gives \(15\), \(20\), and \(25\). The perimeter is \(60\), and \(15^2+20^2=225+400=625=25^2\). 2. A scaled \((5, 12, 13)\) triangle also works. Since \(5+12+13=30\) and \(60\div30=2\), scaling each side by \(2\) gives \(10\), \(24\), and \(26\). The perimeter is \(60\), and \(10^2+24^2=100+576=676=26^2\).

Answer

1. \(15\,\text{m}, 20\,\text{m}, 25\,\text{m}\), because \(15+20+25=60\) and \(15^2+20^2=25^2\). 2. \(10\,\text{m}, 24\,\text{m}, 26\,\text{m}\), because \(10+24+26=60\) and \(10^2+24^2=26^2\).
Pythagorean theorem problem solving 35
Find the missing side length in each right triangle. The legs are \(a\) and \(b\), and the hypotenuse is \(c\). Round each answer to the nearest tenth in the requested unit. a) \(a=9\,\text{cm}\), \(b=14\,\text{cm}\). Find \(c\). b) \(a=0.9\,\text{dm}\), \(c=1.8\,\text{dm}\). Find \(b\). c) \(b=80\,\text{mm}\), \(c=15\,\text{cm}\). Find \(a\) in centimeters.

Hints

- Identify whether the missing side is a leg or the hypotenuse in each part. - Make sure the measurements in a single calculation use the same unit. - What equation relates the three side lengths of any right triangle? - Delay rounding until the final side length in each part.

Solution

1. For part a, \(c=\sqrt{9^2+14^2}=\sqrt{277}\approx16.6\,\text{cm}\). 2. For part b, \(b=\sqrt{1.8^2-0.9^2}=\sqrt{2.43}\approx1.6\,\text{dm}\). 3. For part c, convert \(80\,\text{mm}=8\,\text{cm}\). Then \(a=\sqrt{15^2-8^2}=\sqrt{161}\approx12.7\,\text{cm}\).

Answer

a) \(c\approx16.6\,\text{cm}\) b) \(b\approx1.6\,\text{dm}\) c) \(a\approx12.7\,\text{cm}\)
Pythagorean theorem problem solving 36
A rectangular field is \(7\,\text{yd}\) wide and has a diagonal of \(15\,\text{yd}\). Find the other side length \(b\) and the area \(A\), both to the nearest tenth.

Hints

- A rectangle's diagonal makes two right triangles. - Find the missing length before finding the area. - Do not round the length until the final step.

Solution

1. The diagonal is the hypotenuse, so \(b^2=15^2-7^2=176\). 2. The length is \(b=\sqrt{176}\,\text{yd}\approx13.3\,\text{yd}\). 3. Use the unrounded length for area: \(A=7\sqrt{176}\,\text{yd}^2\approx92.9\,\text{yd}^2\).

Answer

\(b\approx13.3\,\text{yd}\); \(A\approx92.9\,\text{yd}^2\).
Pythagorean theorem problem solving 37
A smartphone screen has a diagonal of \(6.8\,\text{in.}\) and a visible height of \(5.9\,\text{in.}\). a) Find the screen width to the nearest tenth of an inch. b) Find the visible screen area to the nearest tenth of a square inch.

Hints

- The screen's width, height, and diagonal form a right triangle. - Which of those three measurements is opposite the right angle? - Keep the unrounded width when using it in the area calculation.

Solution

1. Let the width be \(w\). Then \(w^2+5.9^2=6.8^2\), so \(w^2=46.24-34.81=11.43\). Therefore, \(w=\sqrt{11.43}\approx3.4\,\text{in.}\). 2. Using the unrounded width, the area is \(5.9\sqrt{11.43}\approx19.9469\,\text{in.}^2\), which rounds to \(19.9\,\text{in.}^2\).

Answer

a) \(3.4\,\text{in.}\) b) \(19.9\,\text{in.}^2\)
Pythagorean theorem problem solving 38
Two right triangles share a leg \(k\). In the first triangle, the hypotenuse is \(13\,\text{cm}\) and another leg is \(7\,\text{cm}\). In the second triangle, the legs are \(k\) and \(9\,\text{cm}\). a) Find the exact length of \(k\). b) Find the exact hypotenuse \(x\) of the second triangle.

Hints

- The same leg appears in both triangles. - Use the first triangle to find \(k^2\). - The second triangle needs \(k^2\), not a rounded value of \(k\).

Solution

1. In the first triangle, \(k^2=13^2-7^2=120\), so \(k=\sqrt{120}\,\text{cm}\). 2. In the second triangle, \(x^2=k^2+9^2=120+81=201\). 3. Therefore, \(x=\sqrt{201}\,\text{cm}\).

Answer

a) \(k=\sqrt{120}\,\text{cm}\). b) \(x=\sqrt{201}\,\text{cm}\).
Pythagorean theorem problem solving 39
A quadrilateral lot is made of two right triangles that share a side \(s\). In the first triangle, \(s\) is a leg, the hypotenuse is \(17\,\text{yd}\), and the other leg is \(9\,\text{yd}\). In the second, the legs are \(s\) and \(11\,\text{yd}\). Find the total area. Give an exact expression and round to the nearest tenth of a square yard.

Hints

- Find the shared side from the first right triangle. - Each triangle's area is half the product of its legs. - Combine the two areas before approximating the shared side.

Solution

1. The shared side satisfies \(s^2=17^2-9^2=208\), so \(s=\sqrt{208}\,\text{yd}\). 2. The triangle areas sum to \(A=\frac{1}{2}(9s)+\frac{1}{2}(11s)=10s\). 3. Thus \(A=10\sqrt{208}\,\text{yd}^2\approx144.2\,\text{yd}^2\).

Answer

\(10\sqrt{208}\,\text{yd}^2\approx144.2\,\text{yd}^2\).
Pythagorean theorem problem solving 40
Point \(R\) is \(5\,\text{cm}\) from line \(m\). Point \(S\) is on the same side of \(m\) as \(R\) and is \(2\,\text{cm}\) from \(m\). a) What is the least possible length of \(\overline{RS}\)? b) Can \(\overline{RS}\) be \(4\,\text{cm}\) long? Justify your answer.

Hints

- When the two points have no sideways offset, how are they positioned relative to line \(m\)? - The difference between the two given distances gives one component of \(\overline{RS}\). - For part b, what relationship connects perpendicular and sideways components to the full segment length?

Solution

1. The least distance occurs when \(R\) and \(S\) lie on the same line perpendicular to \(m\). Their distances from \(m\) differ by \(5-2=3\,\text{cm}\), so the least possible length is \(3\,\text{cm}\). 2. A length of \(4\,\text{cm}\) is possible. The perpendicular component of \(\overline{RS}\) is \(3\,\text{cm}\). If the parallel component is \(x\), then \(x^2+3^2=4^2\), so \(x=\sqrt{7}\,\text{cm}\). Such an offset gives \(RS=4\,\text{cm}\).

Answer

a) \(3\,\text{cm}\) b) Yes. A sideways offset of \(\sqrt{7}\,\text{cm}\) gives \(RS=4\,\text{cm}\).
Pythagorean theorem problem solving 41
Points \(A\) and \(B\) lie on opposite sides of line \(g\). Point \(A\) is \(4\,\text{cm}\) from \(g\), and point \(B\) is \(2\,\text{cm}\) from \(g\). The feet of their perpendiculars to \(g\) are \(7\,\text{cm}\) apart along the line. a) Find \(AB\) exactly and to the nearest hundredth of a centimeter. b) Explain why \(AB\) is longer than the \(6\,\text{cm}\) minimum possible distance between points with these two perpendicular distances on opposite sides of \(g\).

Hints

- Combine the two perpendicular distances because the points are on opposite sides of \(g\). - The separation along \(g\) gives a second perpendicular component of the segment. - Compare the case with a nonzero parallel component to the case when that component is zero.

Solution

1. The perpendicular change from \(A\) to \(B\) is \(4+2=6\,\text{cm}\), while the component parallel to \(g\) is \(7\,\text{cm}\). 2. These perpendicular components form the legs of a right triangle with hypotenuse \(AB\), so \(AB^2=6^2+7^2=85\). 3. Therefore, \(AB=\sqrt{85}\,\text{cm}\approx9.22\,\text{cm}\). 4. The minimum \(6\,\text{cm}\) occurs only when the parallel component is \(0\). Here it is \(7\,\text{cm}\), so the segment must be longer.

Answer

a) \(AB=\sqrt{85}\,\text{cm}\approx9.22\,\text{cm}\). b) The points also differ by \(7\,\text{cm}\) parallel to \(g\), so their separation is the hypotenuse of a right triangle rather than the \(6\,\text{cm}\) perpendicular minimum.
Pythagorean theorem problem solving 42
A rectangular prism has edge lengths \(a=12\,\text{cm}\) and \(b=9\,\text{cm}\). Its space diagonal is \(d=17\,\text{cm}\). a) Find the missing edge length \(c\). b) Find the volume \(V\) of the prism.

Hints

- How are the three edge lengths of a rectangular prism related to its space diagonal? - Rearrange the equation so that the missing edge length is the only unknown. - Which formula gives the volume of a rectangular prism?

Solution

1. The space diagonal satisfies \(d^2=a^2+b^2+c^2\). Thus, \(c=\sqrt{17^2-12^2-9^2}=\sqrt{64}=8\,\text{cm}\). 2. The volume is \(V=abc=12\cdot9\cdot8=864\,\text{cm}^3\).

Answer

a) \(c=8\,\text{cm}\) b) \(V=864\,\text{cm}^3\)
Pythagorean theorem problem solving 43
A right triangle has a hypotenuse of \(29\,\text{cm}\) and one leg of \(21\,\text{cm}\). 1. Find the length of the other leg \(b\). 2. The hypotenuse is increased by \(6\,\text{cm}\) while the \(21\,\text{cm}\) leg stays the same. By how many centimeters does \(b\) increase?

Hints

- First find the unknown side in the original triangle. - Determine the new hypotenuse after the change. - Repeat the calculation for the new triangle, then compare the two leg lengths.

Solution

1. For the original triangle, \(b=\sqrt{29^2-21^2}=\sqrt{841-441}=\sqrt{400}=20\,\text{cm}\). 2. The new hypotenuse is \(29+6=35\,\text{cm}\). 3. The new leg length is \(b_{\text{new}}=\sqrt{35^2-21^2}=\sqrt{1225-441}=\sqrt{784}=28\,\text{cm}\). 4. The increase is \(28-20=8\,\text{cm}\).

Answer

1. \(b=20\,\text{cm}\) 2. The leg increases by \(8\,\text{cm}\).
Pythagorean theorem problem solving 44
Two hikers leave a trail intersection at the same time. Hiker A walks due north at \(4\,\text{mph}\), and Hiker B walks due west at \(3\,\text{mph}\). How far apart are they after \(2\) hours?

Hints

- Draw a sketch of the two paths. - What geometric figure is formed by the paths and the direct segment between the hikers? - First determine how far each hiker travels. - Use the relationship among the side lengths of a right triangle.

Solution

1. Hiker A travels \(4\cdot 2=8\,\text{mi}\). 2. Hiker B travels \(3\cdot 2=6\,\text{mi}\). 3. The two paths are perpendicular, so the hikers' separation is the hypotenuse of a right triangle. 4. Apply the Pythagorean theorem: \(d=\sqrt{8^2+6^2}=\sqrt{64+36}=\sqrt{100}=10\,\text{mi}\).

Answer

The hikers are \(10\,\text{mi}\) apart after \(2\) hours.
Pythagorean theorem problem solving 45
A sailboat starts \(15\) miles due north of a lighthouse and travels due east at \(12\,\text{mph}\). At the same time, a motorboat leaves the lighthouse and travels due north at \(4\,\text{mph}\). Find the distance between the boats after \(2\) hours.

Hints

- Place the lighthouse at the origin of a coordinate plane. - Determine each boat's position after \(2\) hours. - Find the horizontal and vertical separations between the boats. - Use those separations as the legs of a right triangle.

Solution

1. After \(2\) hours, the sailboat is \(12\cdot 2=24\,\text{mi}\) east of its starting point and remains \(15\,\text{mi}\) north of the lighthouse. 2. The motorboat is \(4\cdot 2=8\,\text{mi}\) north of the lighthouse. 3. The horizontal separation is \(24\,\text{mi}\), and the vertical separation is \(15-8=7\,\text{mi}\). 4. Use the Pythagorean theorem: \(d=\sqrt{24^2+7^2}=\sqrt{576+49}=\sqrt{625}=25\,\text{mi}\).

Answer

The boats are \(25\,\text{mi}\) apart after \(2\) hours.
Pythagorean theorem problem solving 46
The diagram shows the end view of an isosceles tent. The tent is \(3.0\,\text{m}\) long. Find the length of each sloping roof side, then find the total area of the two rectangular roof panels.
Figure for problem 531591

Hints

- Use the symmetry of the isosceles end to split the base into two equal parts. - The altitude, half the base, and one sloping side form a right triangle. - Use the sloping side as the width of each rectangular roof panel.

Solution

1. The altitude of the isosceles triangle bisects the \(2.4\,\text{m}\) base, so each half is \(1.2\,\text{m}\). 2. If \(s\) is a sloping side, then \(s^2=1.2^2+1.6^2=4\), so \(s=2.0\,\text{m}\). 3. Each roof panel is \(2.0\,\text{m}\) by \(3.0\,\text{m}\). The two panels have total area \(2\cdot2.0\cdot3.0=12.0\,\text{m}^2\).

Answer

Each sloping side is \(2.0\,\text{m}\); the two roof panels have total area \(12.0\,\text{m}^2\).
Pythagorean theorem problem solving 47
The diagram shows the isosceles triangular end of a prism. Find the perpendicular altitude \(h\), then find the area of the triangular end.
Figure for problem 531595

Hints

- Use the isosceles symmetry to determine how the altitude divides the base. - In one of the resulting right triangles, identify the hypotenuse and the unknown leg. - After finding the altitude, use the triangle area formula.

Solution

1. The altitude of an isosceles triangle bisects the \(6\,\text{cm}\) base, so each half is \(3\,\text{cm}\). 2. Using one half, \(h^2+3^2=5^2\), so \(h^2=16\) and \(h=4\,\text{cm}\). 3. The triangular end area is \(\frac{1}{2}\cdot6\cdot4=12\,\text{cm}^2\).

Answer

\(h=4\,\text{cm}\); triangular end area: \(12\,\text{cm}^2\)
Pythagorean theorem problem solving 48
The diagram shows the symmetric trapezoidal end of a prism. Find the length \(x\) of each slanted side, then find the perimeter of the trapezoid.
Figure for problem 531600

Hints

- Compare the two parallel side lengths and use symmetry to determine the horizontal offset on one side. - The dashed height and that horizontal offset form the legs of a right triangle. - After finding one slanted side, use symmetry when adding the perimeter.

Solution

1. The two bases differ by \(10-4=6\,\text{cm}\). Symmetry splits this difference equally, so the horizontal leg beside either slanted side is \(3\,\text{cm}\). 2. The vertical leg is \(4\,\text{cm}\), so \(x^2=3^2+4^2=25\) and \(x=5\,\text{cm}\). 3. The perimeter is \(10+4+5+5=24\,\text{cm}\).

Answer

Each slanted side is \(5\,\text{cm}\); perimeter: \(24\,\text{cm}\)
Pythagorean theorem problem solving 49
The diagram shows the house-shaped end of a prism. Find the length \(x\) of each slanted roof edge, then find the total length of the two slanted roof edges.
Figure for problem 531622

Hints

- Compare the total height with the wall height to determine the roof's vertical rise. - Use symmetry to determine the horizontal run from one wall to the peak. - Those two distances are perpendicular legs for the slanted roof edge.

Solution

1. The roof rises \(8-5=3\,\text{cm}\) above the walls. Symmetry makes the horizontal run from a wall to the peak half of \(8\,\text{cm}\), or \(4\,\text{cm}\). 2. Thus \(x^2=4^2+3^2=25\), so \(x=5\,\text{cm}\). 3. The two equal roof edges have total length \(2\cdot5=10\,\text{cm}\).

Answer

Each slanted roof edge is \(5\,\text{cm}\); together they measure \(10\,\text{cm}\).
Pythagorean theorem problem solving 50
The diagram shows the pentagonal end of a rooftop cargo box. Find the slanted top edge \(x\), then find the perimeter of the pentagonal end.
Figure for problem 535911

Hints

- Compare the full bottom width with the horizontal top segment to obtain one perpendicular change. - Compare the two vertical side lengths to obtain the other perpendicular change. - Use those changes as the legs of a right triangle for the slanted edge. - Add all five boundary edges after finding the missing one.

Solution

1. The horizontal change across the slanted section is \(120-80=40\,\text{cm}\), and the vertical change is \(50-20=30\,\text{cm}\). 2. Therefore, \(x^2=40^2+30^2=2500\), so \(x=50\,\text{cm}\). 3. The pentagonal end perimeter is \(120+20+50+80+50=320\,\text{cm}\).

Answer

\(x=50\,\text{cm}\); perimeter: \(320\,\text{cm}\)
Pythagorean theorem problem solving 51
Find the missing side length \(x\) and give the result in meters to the nearest hundredth.
Figure for problem 536439

Hints

- Convert the displayed measurements to the same unit. - Decide whether \(x\) is a leg or the hypotenuse from the right-angle mark. - Round only after taking the square root.

Solution

1. Convert the known leg to meters: \(10\,\text{dm}=1\,\text{m}\). The hypotenuse is \(2.7\,\text{m}\). 2. The right-triangle relation gives \(x^2+1^2=2.7^2\), so \(x^2=6.29\). 3. Therefore, \(x=\sqrt{6.29}\approx2.51\,\text{m}\).

Answer

\(x\approx2.51\,\text{m}\)
Pythagorean theorem problem solving 52
Find the side length \(x\) in millimeters to the nearest tenth.
Figure for problem 536440

Hints

- Put the displayed measurements in millimeters before calculating. - Use the right-angle mark to identify the hypotenuse. - Keep the square root unrounded until the requested precision.

Solution

1. Convert the known leg to millimeters: \(1.5\,\text{cm}=15\,\text{mm}\). The hypotenuse is \(41\,\text{mm}\). 2. The right-triangle relation gives \(x^2+15^2=41^2\), so \(x^2=1456\). 3. Therefore, \(x=\sqrt{1456}\approx38.2\,\text{mm}\).

Answer

\(x\approx38.2\,\text{mm}\)
Pythagorean theorem problem solving 53
A \(10\,\text{m}\) ladder leans against a wall. Its base is \(6\,\text{m}\) from the wall. Mia calculates the height \(h\) where the ladder touches the wall: \(h^2=10^2+6^2=136\), so \(h=\sqrt{136}\approx11.7\,\text{m}\). Explain why this result is unreasonable and find the correct height.
Figure for problem 536446

Hints

- Identify the right angle and determine which side is the hypotenuse. - Compare Mia's result with the ladder length. - When a leg is unknown, decide whether to add or subtract squared lengths.

Solution

1. The ladder is the hypotenuse, so a leg cannot be longer than the \(10\,\text{m}\) ladder. A height of \(11.7\,\text{m}\) is therefore impossible. 2. Mia added the square of the known leg instead of subtracting it from the square of the hypotenuse. 3. The correct equation is \(h^2=10^2-6^2=100-36=64\). 4. Therefore, \(h=\sqrt{64}=8\,\text{m}\).

Answer

Mia's result is unreasonable because a leg cannot be longer than the hypotenuse. The correct height is \(h=8\,\text{m}\).
Pythagorean theorem problem solving 54
Find the length of \(x\). All measurements are in centimeters.
Figure for problem 536478

Hints

- First find the common vertical leg of the two right triangles. - Use the total base length for the larger triangle.

Solution

1. Let \(h\) be the vertical leg shared by the two right triangles. In the smaller triangle, \(h^2=12.5^2-3.5^2=156.25-12.25=144\), so \(h=12\,\text{cm}\). 2. The base of the larger triangle is \(3.5+1.5=5\,\text{cm}\). 3. Apply the Pythagorean theorem to the larger triangle: \(x^2=12^2+5^2=169\). Therefore, \(x=13\,\text{cm}\).

Answer

\(x=13\,\text{cm}\)
Pythagorean theorem problem solving 55
Find the length of the marked segment \(x\) to the nearest tenth. All measurements are in centimeters.
Figure for problem 536609

Hints

- The two right triangles share the same vertical segment. - What can the left triangle tell you about the square of that shared length? - Carry that squared value into the second triangle before rounding anything.

Solution

1. Let \(h\) be the vertical segment shared by the two right triangles. In the left triangle, \(h^2+6^2=11^2\), so \(h^2=85\). 2. In the right triangle, \(x^2=h^2+13^2=85+169=254\). 3. Therefore, \(x=\sqrt{254}\approx15.9\,\text{cm}\).

Answer

\(x\approx15.9\,\text{cm}\)
Pythagorean theorem problem solving 56
The diagram shows a right triangle with two side lengths labeled. Find its area to the nearest hundredth of a square centimeter.
Figure for problem 536992

Hints

- Identify which labeled side is the hypotenuse before finding the missing leg. - Keep the missing leg in radical form until you use it as a base or height. - Round the area, not the missing leg, at the final step.

Solution

1. Let the unlabeled leg be \(b\). Then \(b^2=15^2-8^2=225-64=161\), so \(b=\sqrt{161}\,\text{cm}\). 2. The area is \(A=\frac{1}{2}\cdot8\cdot\sqrt{161}=4\sqrt{161}\,\text{cm}^2\approx50.75\,\text{cm}^2\).

Answer

The area is approximately \(50.75\,\text{cm}^2\).
Pythagorean theorem problem solving 57
An isosceles trapezoid is supposed to have a perimeter of \(24\,\text{cm}\). Its two legs and its shorter base are all the same length. Its longer base is three times the length of each of those shorter sides. Find the resulting side lengths. Then use the Pythagorean theorem to determine whether a nondegenerate trapezoid with those side lengths can exist.

Hints

- Express all four side lengths using the common shorter length. - After finding the side lengths, drop perpendiculars from the endpoints of the shorter base. - How much of the longer base extends beyond the shorter base on each side? - Use a leg of the trapezoid as the hypotenuse of one of the resulting right triangles.

Solution

1. Let \(x\) be the common length of each leg and the shorter base. Then the longer base is \(3x\). The perimeter equation is \(x+x+x+3x=24\), so \(6x=24\) and \(x=4\). 2. The side lengths are therefore \(4\,\text{cm}\), \(4\,\text{cm}\), \(4\,\text{cm}\), and \(12\,\text{cm}\). 3. In an isosceles trapezoid, dropping perpendiculars from the shorter base splits the extra base length equally. Each horizontal leg of the resulting right triangles is \(\frac{12-4}{2}=4\,\text{cm}\). 4. If \(h\) is the trapezoid's height, the Pythagorean theorem gives \(h^2+4^2=4^2\). Thus \(h^2=0\), so \(h=0\). 5. A height of zero means the figure collapses into a line segment, so no nondegenerate trapezoid with positive area exists.

Answer

The longer base is \(12\,\text{cm}\), and the other three sides are \(4\,\text{cm}\) each. No nondegenerate trapezoid exists because the Pythagorean theorem gives height \(0\,\text{cm}\).
Pythagorean theorem problem solving 58
A loop of rope is divided into \(12\) equal segments and can be arranged as a right triangle with side lengths \(3\), \(4\), and \(5\) segments. Now consider ropes with different total numbers of equal segments. a) A claim says that a rope with \(10\) segments can form a right triangle with whole-number side lengths. Explain mathematically why this is impossible. b) Another rope has \(30\) segments. Show that it can form a right triangle with whole-number side lengths whose side-length ratio is not \(3:4:5\).

Hints

- Use the triangle inequality to limit the possible length of the longest side when the perimeter is \(10\). - List the whole-number triples that add to \(10\) after applying that limit. - For part b, look for a Pythagorean triple that is not a scaled \((3,4,5)\) triple. - Compare corresponding side ratios to decide whether two triangles are scaled copies.

Solution

1. For part a, let \(a\le b\le c\) be whole-number side lengths with \(a+b+c=10\). The triangle inequality gives \(a+b>c\), so \(10-c>c\) and \(c<5\). Also \(3c\ge10\), so \(c\ge4\). Thus \(c=4\). 2. Then \(a+b=6\), giving only \((a,b)=(2,4)\) or \((3,3)\). Neither works: \(2^2+4^2=20\ne16\), and \(3^2+3^2=18\ne16\). Therefore, no whole-number right triangle has perimeter \(10\). 3. For part b, the side lengths \(5\), \(12\), and \(13\) have perimeter \(30\), and \(5^2+12^2=169=13^2\). The ratio \(5:12:13\) is not a scaled version of \(3:4:5\), so it meets the requirement.

Answer

a) No whole-number right triangle has perimeter \(10\); the only possible longest side is \(4\), and the resulting triples do not satisfy the Pythagorean theorem. b) \(5,12,13\) works because \(5+12+13=30\) and \(5^2+12^2=13^2\); its ratio is not \(3:4:5\).
Pythagorean theorem problem solving 59
A television must fit in a cabinet opening that is \(36\,\text{in.}\) wide and \(24\,\text{in.}\) high. The television has a \(1\,\text{in.}\) bezel on all four sides of the screen. What is the largest whole-number screen size, measured diagonally, for a \(16:9\) television that will fit?

Hints

- Subtract the bezel twice from each cabinet dimension. - Use the \(16:9\) ratio to determine which dimension limits the screen. - Find the diagonal with the Pythagorean theorem, then choose the greatest whole number that does not exceed it.

Solution

1. The maximum screen dimensions are \(36-2\cdot 1=34\,\text{in.}\) wide and \(24-2\cdot 1=22\,\text{in.}\) high. 2. At the maximum width, a \(16:9\) screen has height \(34\cdot\frac{9}{16}=19.125\,\text{in.}\), which is less than \(22\,\text{in.}\). Thus width is the limiting dimension. 3. The maximum screen diagonal is \(d=\sqrt{34^2+19.125^2}\approx 39.01\,\text{in.}\). 4. Therefore, the largest whole-number screen size that fits is \(39\,\text{in.}\).

Answer

The largest whole-number screen size is \(39\,\text{in.}\).
Pythagorean theorem problem solving 60
A rectangular prism has edge lengths \(16\,\text{cm}\), \(8\,\text{cm}\), and \(4\,\text{cm}\). A cube has the same volume. a) Find the cube's edge length \(s\). b) Find both space diagonals, first as exact square roots and then to the nearest hundredth of a centimeter. How much longer is the rectangular prism's diagonal? Round the difference to the nearest hundredth too.

Hints

- Equal volumes let you find the cube's edge from the prism volume. - A space diagonal combines three perpendicular edge lengths. - Subtract before rounding the difference.

Solution

1. The prism volume is \(16\cdot8\cdot4=512\,\text{cm}^3\), so \(s^3=512\) and \(s=8\,\text{cm}\). 2. In the prism, first find a face diagonal: \(d_f^2=16^2+8^2=320\). The face diagonal and third edge form a right triangle, so the space diagonal is \(\sqrt{320+4^2}=\sqrt{336}\,\text{cm}\approx18.33\,\text{cm}\). 3. In the cube, first find a face diagonal squared: \(8^2+8^2=128\). Then its space diagonal is \(\sqrt{128+8^2}=\sqrt{192}\,\text{cm}\approx13.86\,\text{cm}\). 4. Subtract the unrounded lengths: \(\sqrt{336}-\sqrt{192}\approx4.47\,\text{cm}\).

Answer

a) \(s=8\,\text{cm}\). b) Prism diagonal \(\sqrt{336}\,\text{cm}\approx18.33\,\text{cm}\); cube diagonal \(\sqrt{192}\,\text{cm}\approx13.86\,\text{cm}\); difference \(\sqrt{336}-\sqrt{192}\,\text{cm}\approx4.47\,\text{cm}\).

All problems may be used, copied and printed free of charge for school and tutoring, including paid tutoring. Commercial adaptations as well as publication or redistribution on the internet are not permitted.