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.

Distance formula from Pythagorean

Learning goals

  • Derives coordinate distance from horizontal and vertical differences.
  • Finds distance between two points from their coordinate differences.
  • Uses the Pythagorean theorem to justify the formula.
  • Checks distance as nonnegative and symmetric in point order.

Click problems to add them to your worksheet.

Distance formula from Pythagorean 1
Points \(A\) and \(B\) are shown on the coordinate plane. What are the horizontal distance and the vertical distance between the two points?
Figure for problem 552198

Hints

- Read both ordered pairs from the graph. - Compare the x-coordinates for the horizontal distance and the y-coordinates for the vertical distance.

Solution

1. From the graph, \(A(-2,1)\) and \(B(1,5)\). 2. The horizontal distance is \(|1-(-2)|=3\), and the vertical distance is \(|5-1|=4\).

Answer

Horizontal distance: \(3\) units; vertical distance: \(4\) units
Distance formula from Pythagorean 2
The graph shows points \(P\) and \(Q\). Write a Pythagorean expression for the straight-line distance \(PQ\). Do not evaluate the square root.
Figure for problem 552199

Hints

- Treat the dashed horizontal and vertical segments as perpendicular legs. - Use the coordinate grid to determine the two leg lengths. - The straight segment \(PQ\) is the hypotenuse of that right triangle.

Solution

The dashed horizontal and vertical segments have lengths \(8\) and \(6\), so \(PQ=\sqrt{8^2+6^2}\).

Answer

\(PQ=\sqrt{8^2+6^2}\)
Distance formula from Pythagorean 3
A Wi-Fi router is located at \(R(2, 3)\) on a coordinate grid measured in meters. Its outdoor signal reaches points up to \(5\,\text{m}\) from the router. Use the distance formula to determine whether a laptop at \(L(-2, 6)\) is within range. Justify your answer.

Hints

- Interpret the range as a maximum allowable distance. - Substitute both ordered pairs into the distance formula. - Be careful when subtracting a negative coordinate.

Solution

1. Use the distance formula: \(d=\sqrt{(-2-2)^2+(6-3)^2}\). 2. Simplify: \(d=\sqrt{(-4)^2+3^2}=\sqrt{16+9}=\sqrt{25}=5\,\text{m}\). 3. The distance is exactly the router's maximum range, so the laptop is within range.

Answer

Yes. The laptop is exactly \(5\,\text{m}\) from the router, so it is within range.
Distance formula from Pythagorean 4
A drone flies directly from \(K(-6, -4)\) to \(L(5, 2)\). Find the length of the flight path to the nearest tenth of a coordinate unit.

Hints

- Find the horizontal and vertical changes from the ordered pairs. - Those two changes form perpendicular legs of a right triangle whose hypotenuse is the direct path. - Keep the square root unrounded until the requested precision.

Solution

1. The horizontal change is \(5-(-6)=11\), and the vertical change is \(2-(-4)=6\). 2. The flight path is the hypotenuse of the right triangle formed by those changes, so \(KL=\sqrt{11^2+6^2}=\sqrt{157}\approx12.530\). 3. Rounded to the nearest tenth, the flight path is \(12.5\) coordinate units.

Answer

The flight path is approximately \(12.5\) coordinate units long.
Distance formula from Pythagorean 5
Points \(A\), \(B\), and \(C\) are shown on the coordinate plane, with \(C\) forming a right triangle that can be used to find the distance from \(A\) to \(B\). a) Read the coordinates and find the leg lengths \(AC\) and \(BC\). b) Use them to find the hypotenuse length \(AB\).
Figure for problem 536447

Hints

- Read each labeled point's coordinates from the graph. - Compare the x-coordinates and y-coordinates to find the two perpendicular leg lengths. - What relationship connects the two perpendicular legs to the diagonal segment?

Solution

1. From the graph, \(A(1, 1)\), \(B(13, 6)\), and \(C(13, 1)\). 2. The horizontal leg has length \(AC=|13-1|=12\), and the vertical leg has length \(BC=|6-1|=5\). 3. Then \(AB=\sqrt{12^2+5^2}=\sqrt{169}=13\).

Answer

a) \(AC=12\) and \(BC=5\) b) \(AB=13\)
Distance formula from Pythagorean 6
Two boundary markers are at \(G_1(-2, 1)\) and \(G_2(3, 5)\). How far apart are the markers? Round to the nearest hundredth.

Hints

- Picture the direct segment as the hypotenuse of a right triangle. - Find the horizontal and vertical changes from the coordinates. - Take the square root and round only at the end.

Solution

1. The horizontal change is \(3-(-2)=5\), and the vertical change is \(5-1=4\). 2. The distance is \(d=\sqrt{5^2+4^2}=\sqrt{41}\). 3. Since \(\sqrt{41}\approx6.4031\), the distance rounds to \(6.40\) units.

Answer

The markers are approximately \(6.40\) units apart.
Distance formula from Pythagorean 7
Points \(A\), \(B\), and \(C\) are shown on the coordinate plane. Compare the lengths of \(\overline{AB}\) and \(\overline{AC}\). Which segment is longer?
Figure for problem 536882

Hints

- Read the coordinates of the labeled points from the graph. - A horizontal segment can be measured from its x-coordinates. - Use a right triangle or the distance formula for the oblique segment.

Solution

1. From the graph, \(A(1,1)\), \(B(5,1)\), and \(C(3,4)\). 2. Since \(A\) and \(B\) have the same y-coordinate, \(AB=|5-1|=4\). 3. Also, \(AC=\sqrt{(3-1)^2+(4-1)^2}=\sqrt{13}\approx3.61\). 4. Since \(4>3.61\), \(\overline{AB}\) is longer.

Answer

\(\overline{AB}\) is longer because \(AB=4\) and \(AC=\sqrt{13}\approx3.61\).
Distance formula from Pythagorean 8
Segments \(\overline{AB}\) and \(\overline{CD}\) are shown on the coordinate plane. Determine whether they have the same length. Justify your answer from the coordinates in the graph.
Figure for problem 536916

Hints

- Read all four endpoints from the graph. - Find the horizontal and vertical changes for each segment. - Compare the two exact distances before using decimals.

Solution

1. From the graph, \(A(0,0)\), \(B(2,3)\), \(C(4,1)\), and \(D(7,3)\). 2. For \(\overline{AB}\), the changes are \(2\) and \(3\), so \(AB=\sqrt{2^2+3^2}=\sqrt{13}\). 3. For \(\overline{CD}\), the changes are \(3\) and \(2\), so \(CD=\sqrt{3^2+2^2}=\sqrt{13}\). 4. Therefore, the segments have the same length.

Answer

Yes. Both segments have length \(\sqrt{13}\).
Distance formula from Pythagorean 9
Find point \(R\), where a horizontal line through \(P\) meets a vertical line through \(Q\). Give \(R\)'s coordinates and the lengths \(PR\) and \(RQ\).
Figure for problem 560002

Hints

- If you choose \(R\) in the wrong row, could \(PR\) still be horizontal? - Can you check your corner by tracing a vertical path from \(R\) toward \(Q\)? - How can you read a segment's length from the grid without measuring the picture?

Solution

1. The grid shows \(P(-3,2)\) and \(Q(2,-2)\). 2. Since \(R\) lies on the horizontal line through \(P\), it has \(y=2\). Since it lies on the vertical line through \(Q\), it has \(x=2\). Thus \(R(2,2)\). 3. \(PR=5\) units horizontally and \(RQ=4\) units vertically.

Answer

\(R(2,2)\), \(PR=5\) units, \(RQ=4\) units.
Distance formula from Pythagorean 10
Segment \(AB\) is the hypotenuse of a right triangle you can form with horizontal and vertical grid lines. Give the lengths of the two legs and write a Pythagorean equation for \(AB\). Do not solve the equation.
Figure for problem 560003

Hints

- Where could you put a third corner so that two grid-aligned segments meet at a right angle? - Could you place the right-angle corner in a different spot? Would that change the lengths of the two legs?

Solution

1. The coordinates are \(A(-1,1)\) and \(B(3,4)\). 2. The horizontal leg is \(3-(-1)=4\) units and the vertical leg is \(4-1=3\) units. 3. Therefore, \(AB^2=4^2+3^2\).

Answer

The legs are \(4\) and \(3\) units; \(AB^2=4^2+3^2\).
Distance formula from Pythagorean 11
Triangle \(ABC\) has vertices \(A(-2, 1)\), \(B(4, 1)\), and \(C(1, 6)\). a) Find the exact perimeter of triangle \(ABC\). b) Determine whether the triangle is isosceles. Justify your answer using the side lengths.

Hints

- One side is horizontal, so its length can be read from the x-coordinates. - For each slanted side, compare both the horizontal and vertical coordinate changes. - An isosceles conclusion needs evidence that two side lengths are equal.

Solution

1. Since \(A\) and \(B\) have the same y-coordinate, \(AB=|4-(-2)|=6\). 2. The other two side lengths are \(AC=\sqrt{(1-(-2))^2+(6-1)^2}=\sqrt{34}\) and \(BC=\sqrt{(1-4)^2+(6-1)^2}=\sqrt{34}\). 3. Therefore, the perimeter is \(6+2\sqrt{34}\) units. 4. Since \(AC=BC=\sqrt{34}\), triangle \(ABC\) is isosceles.

Answer

a) \(6+2\sqrt{34}\) units b) Yes. The triangle is isosceles because \(AC=BC=\sqrt{34}\).
Distance formula from Pythagorean 12
Points \(A(2, 2)\), \(B(8, 2)\), and \(C(5, 6)\) form triangle \(ABC\). a) Find the length of \(\overline{AB}\). b) Use the Pythagorean theorem to find the lengths of \(\overline{AC}\) and \(\overline{BC}\). c) Classify the triangle by its side lengths.

Hints

- A horizontal segment's length is the difference of its x-coordinates. - Use the horizontal and vertical changes as the legs of a right triangle. - A triangle with two equal side lengths has a special classification.

Solution

1. Segment \(\overline{AB}\) is horizontal, so \(AB=8-2=6\) units. 2. From \(A\) to \(C\), the horizontal change is \(3\) and the vertical change is \(4\), so \(AC=\sqrt{3^2+4^2}=5\) units. From \(B\) to \(C\), the horizontal change has magnitude \(3\) and the vertical change is \(4\), so \(BC=5\) units. 3. Since \(AC=BC\), the triangle is isosceles.

Answer

a) \(AB=6\) units b) \(AC=5\) units and \(BC=5\) units c) The triangle is isosceles.
Distance formula from Pythagorean 13
A digital coordinate map shows Mia at point \(P\), Ben at point \(Q\), and point \(R\), which forms right triangle \(PQR\). One coordinate unit represents exactly \(10\,\text{m}\). a) Read the coordinates from the graph and find the actual straight-line distance between Mia and Ben in meters. b) Find the actual area of triangle \(PQR\) in square meters.
Figure for problem 532240

Hints

- Read the coordinates of the labeled points from the graph first. - Use the horizontal and vertical changes as the legs of a right triangle. - Convert coordinate units to meters before calculating the real-world area. - Use the area formula for a right triangle.

Solution

1. From the graph, \(P(-4, -2)\), \(Q(4, 4)\), and \(R(4, -2)\). The horizontal and vertical leg lengths are \(8\) and \(6\) coordinate units, so \(PQ=\sqrt{8^2+6^2}=10\) coordinate units. Since each unit represents \(10\,\text{m}\), the actual distance is \(100\,\text{m}\). 2. The actual leg lengths are \(80\,\text{m}\) and \(60\,\text{m}\). Thus, \(A=\frac{1}{2}\cdot80\cdot60=2400\,\text{m}^2\).

Answer

a) \(100\,\text{m}\) b) \(2400\,\text{m}^2\)
Distance formula from Pythagorean 14
The graph marks the start \(A\) of a planned arrow. Its length will be \(\sqrt{34}\) units, and it will point up and to the right with a horizontal change of \(3\) units. How far will it rise? Find its endpoint \(B\).
Figure for problem 536915

Hints

- Read the marked starting coordinates. - The horizontal change, vertical change, and arrow length form a right triangle. - Choose a positive vertical change because the arrow points upward.

Solution

1. The grid places the start at \(A(1,2)\). 2. For upward change \(\Delta y\), \((\sqrt{34})^2=3^2+(\Delta y)^2\), so \((\Delta y)^2=25\) and \(\Delta y=5\). 3. The endpoint is \(B(1+3,2+5)=(4,7)\).

Answer

The arrow rises \(5\) units; \(B(4,7)\).
Distance formula from Pythagorean 15
Points \(P(x_1, y_1)\) and \(Q(x_2, y_2)\) are any two points in the coordinate plane. Derive a formula for the distance \(d\) between \(P\) and \(Q\) by using the horizontal change, the vertical change, and the Pythagorean theorem. Then explain why the formula still works if one or both coordinate differences are negative.

Hints

- Express the horizontal and vertical changes symbolically before introducing the distance. - Think of those two changes as perpendicular legs of a right triangle. - After writing the squared relationship, use the fact that a distance cannot be negative.

Solution

1. The horizontal change from \(P\) to \(Q\) is \(x_2-x_1\), and the vertical change is \(y_2-y_1\). 2. These changes can be used as the legs of a right triangle whose hypotenuse has length \(d\). 3. By the Pythagorean theorem, \(d^2=(x_2-x_1)^2+(y_2-y_1)^2\). 4. Distance is nonnegative, so \(d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\). 5. If a coordinate difference is negative, squaring it gives the same value as squaring its positive magnitude, so the formula is unchanged.

Answer

\(d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\). Negative coordinate differences do not change the distance because they are squared.
Distance formula from Pythagorean 16
Find the distance between \(P(-2, 1)\) and \(Q(1, 5)\). Show both coordinate differences in your calculation. Explain why reversing the points gives the same distance.

Hints

- Find both the horizontal and vertical changes between the points. - What type of triangle can you use to find a slanted segment? - What changes if you subtract the coordinates in the opposite order?

Solution

1. From \(P\) to \(Q\), the horizontal change is \(3\) and the vertical change is \(4\). 2. By the Pythagorean theorem, \(PQ=\sqrt{3^2+4^2}=5\) units. 3. Reversing direction changes both signs but not the squared changes, so \(QP=5\) units too.

Answer

Horizontal change: \(1-(-2)=3\); vertical change: \(5-1=4\). Thus \(PQ=\sqrt{3^2+4^2}=5\) units. Reversing direction changes the signs of the differences but not their squares, so \(QP=5\) units too.
Distance formula from Pythagorean 17
A student tries to find the distance from \(P(-2,-1)\) to \(Q(1,3)\). They use a horizontal change of \(3\), but a vertical change of \(2\), and answer \(\sqrt{13}\) units. Identify the coordinate error and give the correct distance.

Hints

- Look at the sign of each \(y\)-coordinate. - Subtract the starting coordinate from the ending coordinate with parentheses. - Recompute the diagonal using the corrected legs.

Solution

1. The horizontal change is \(1-(-2)=3\). 2. The vertical change is \(3-(-1)=4\), not \(2\); subtracting a negative number adds its opposite. 3. The distance is \(\sqrt{3^2+4^2}=5\) units.

Answer

The vertical change is \(4\), not \(2\), because \(3-(-1)=4\). The distance is \(5\) units.
Distance formula from Pythagorean 18
Points \(A(1, 2)\) and \(B(k, 6)\) are exactly \(7\) units apart. Find all possible exact values of \(k\).

Hints

- The unknown x-coordinate controls only the horizontal change between the points. - Use the stated distance together with the known vertical change. - Why should there be one possible point to the left and another to the right?

Solution

1. The horizontal change is \(k-1\), and the vertical change is \(6-2=4\). 2. The distance condition gives \(7^2=(k-1)^2+4^2\). 3. Thus \(49=(k-1)^2+16\), so \((k-1)^2=33\). 4. Therefore, \(k-1=\sqrt{33}\) or \(k-1=-\sqrt{33}\), giving \(k=1+\sqrt{33}\) or \(k=1-\sqrt{33}\).

Answer

\(k=1+\sqrt{33}\) or \(k=1-\sqrt{33}\).
Distance formula from Pythagorean 19
Triangle \(OAB\) is shown on the coordinate plane. a) Read the coordinates and find the lengths of all three sides. b) Use the side lengths to determine \(\angle AOB\). Justify your conclusion.
Figure for problem 537186

Hints

- Read the three coordinates from the graph before calculating. - Compare the squares of the side lengths to test for a right angle. - Equal side lengths imply equal opposite angles. - Use the angle sum of a triangle after identifying the right angle.

Solution

1. From the graph, \(O(0, 0)\), \(A(3, 1)\), and \(B(1, 2)\). 2. The side lengths are \(OA=\sqrt{3^2+1^2}=\sqrt{10}\), \(OB=\sqrt{1^2+2^2}=\sqrt{5}\), and \(AB=\sqrt{(3-1)^2+(1-2)^2}=\sqrt{5}\). 3. Since \(OB^2+AB^2=5+5=10=OA^2\), the triangle is right with the right angle at \(B\). 4. Also, \(OB=AB\), so the two acute angles are equal. They sum to \(90^\circ\), so \(\angle AOB=45^\circ\).

Answer

a) \(OA=\sqrt{10}\), \(OB=\sqrt{5}\), and \(AB=\sqrt{5}\) b) \(\angle AOB=45^\circ\)

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.