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Polygons on the coordinate plane

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5109486
The points \(A(2, 1)\), \(B(7, 1)\), and \(C(8, 4)\) are shown on a coordinate plane. a) Find the coordinates of a fourth point \(D\) so that \(ABCD\) is a parallelogram. b) Find the length of the height \(h\) perpendicular to side \(AB\). c) Find the area of parallelogram \(ABCD\).

Hints

- What is true about opposite sides of a parallelogram? - What is the vertical distance from the lower side to the upper side? - What formula gives the area of a parallelogram?

Solution

1. Segment \(AB\) moves \(5\) units to the right. In a parallelogram, the opposite side must be parallel and equal in length, so move \(5\) units left from \(C(8, 4)\). This gives \(D(3, 4)\). 2. Side \(AB\) lies on \(y=1\), and side \(CD\) lies on \(y=4\). Their perpendicular distance is \(4-1=3\) units, so \(h=3\) units. 3. The base is \(7-2=5\) units. Therefore, \(A=bh=5\times3=15\) square units.

Answer

a) \(D(3, 4)\) b) \(h=3\) units c) \(A=15\) square units
5109516
Parallelogram \(ABCD\) has vertices \(A(1, 1)\), \(B(7, 1)\), \(C(9, 5)\), and \(D(3, 5)\) on a coordinate plane where each unit represents \(1\,\text{cm}\). a) Graph the parallelogram. b) Use the coordinates to find the base length \(b=AB\) and the corresponding height \(h\). c) Find the area of the parallelogram. d) Imagine sliding the upper side \(CD\) to the right while keeping it parallel to \(AB\). If the base and height stay the same, how does the area change? Explain.

Hints

- How can you find the distance between two points on a horizontal line? - What does the height of a parallelogram represent? - Which measurements determine the area in \(A=bh\)?

Solution

1. Plot \(A(1, 1)\), \(B(7, 1)\), \(C(9, 5)\), and \(D(3, 5)\), then connect the points in order to graph the parallelogram. 2. Since \(A\) and \(B\) have the same y-coordinate, \(AB=7-1=6\,\text{cm}\). 3. The height is the perpendicular distance between the horizontal lines \(y=1\) and \(y=5\): \(h=5-1=4\,\text{cm}\). 4. The area is \(A=bh=6\times4=24\,\text{cm}^2\). 5. Sliding the upper side horizontally changes the slant of the parallelogram but not its base or height. Therefore, the area remains \(24\,\text{cm}^2\).

Answer

a) A graph of the parallelogram with the given vertices b) \(b=6\,\text{cm}\), \(h=4\,\text{cm}\) c) \(A=24\,\text{cm}^2\) d) The area stays \(24\,\text{cm}^2\) because the base and perpendicular height do not change.
5109666
Find the area of rhombus \(ABCD\) with vertices \(A(2, 5)\), \(B(6, 2)\), \(C(10, 5)\), and \(D(6, 8)\) on a coordinate plane.

Hints

- Can you read the diagonal lengths from the coordinates? - How are the diagonals positioned on the coordinate plane? - What formula uses the two diagonals to find the area of a rhombus? - Can you decompose the rhombus into two or four congruent triangles?

Solution

1. Diagonal \(AC\) is horizontal, and diagonal \(BD\) is vertical. 2. Their lengths are \(AC=10-2=8\) units and \(BD=8-2=6\) units. 3. Use the rhombus area formula: \(A=\frac{1}{2}d_1d_2\). 4. Therefore, \(A=\frac{1}{2}\times8\times6=24\) square units.

Answer

The area of the rhombus is \(24\) square units.
5109836
Trapezoid \(ABCD\) has vertices \(A(1, 1)\), \(B(9, 1)\), \(C(6, 4)\), and \(D(4, 4)\). a) Find the area of the trapezoid. b) Points \(C\) and \(D\) are moved to \(C_1(7, 4)\) and \(D_1(3, 4)\). Find the area of trapezoid \(ABC_1D_1\). c) By how many square units did the area increase?

Hints

- Use half the sum of the parallel side lengths times the height. - Which coordinate differences give the lengths of the parallel sides? - Does the height change when the two upper points move horizontally?

Solution

1. In \(ABCD\), the parallel sides have lengths \(AB=9-1=8\) units and \(CD=6-4=2\) units. The height is \(4-1=3\) units. Thus, \(A=\frac{1}{2}(8+2)\times3=15\) square units. 2. In \(ABC_1D_1\), the lower base is still \(8\) units, the upper base is \(7-3=4\) units, and the height is still \(3\) units. Thus, \(A_1=\frac{1}{2}(8+4)\times3=18\) square units. 3. The increase is \(18-15=3\) square units.

Answer

a) \(15\) square units b) \(18\) square units c) The area increased by \(3\) square units.
5109846
The points \(A(1, 2)\), \(B(7, 2)\), and \(C(4, 6)\) are given. a) Graph triangle \(ABC\) on a coordinate plane where each unit represents \(1\,\text{cm}\). b) Find the length of base \(AB\) and its corresponding height \(h\). c) Find the area of triangle \(ABC\).

Hints

- How do you find the distance between two points on a horizontal line? - A height is perpendicular to its base. - What is the area formula for a triangle?

Solution

1. Plot \(A(1, 2)\), \(B(7, 2)\), and \(C(4, 6)\), then connect the points to graph triangle \(ABC\). 2. Segment \(AB\) is horizontal, so its length is \(7-1=6\,\text{cm}\). 3. The height is the vertical distance from \(C\) to line \(AB\): \(6-2=4\,\text{cm}\). 4. The area is \(A=\frac{1}{2}bh=\frac{1}{2}\times6\times4=12\,\text{cm}^2\).

Answer

a) A graph of triangle \(ABC\) with the given vertices b) \(AB=6\,\text{cm}\), \(h=4\,\text{cm}\) c) \(A=12\,\text{cm}^2\)
5110176
Trapezoid \(ABCD\) has vertices \(A(2, 1)\), \(B(2, 6)\), \(C(5, 5)\), and \(D(5, 2)\). Graph the trapezoid and find its area.

Hints

- Which sides are parallel? - How do you find the length of a vertical segment from its coordinates? - What is the distance between the two vertical lines? - Use the trapezoid area formula.

Solution

1. Plot \(A(2, 1)\), \(B(2, 6)\), \(C(5, 5)\), and \(D(5, 2)\), then connect the points in order to graph the trapezoid. 2. Sides \(AB\) and \(CD\) are vertical and parallel. 3. Their lengths are \(AB=6-1=5\) units and \(CD=5-2=3\) units. 4. The height is the horizontal distance between \(x=2\) and \(x=5\), which is \(3\) units. 5. The area is \(A=\frac{1}{2}(5+3)\times3=12\) square units.

Answer

A graph of trapezoid \(ABCD\) with the given vertices; the area is \(12\) square units.
5110926
A parallelogram has vertices \(A(1, 1)\), \(B(8, 1)\), and \(D(3, 5)\). a) Find the coordinates of vertex \(C\) and the area of the parallelogram. b) A rectangle lies above base \(AB\) and has the same base and area as the parallelogram. Give the coordinates of its other two vertices, \(C_1\) and \(D_1\).

Hints

- Opposite sides of a parallelogram are parallel and congruent. - Which base and height are easiest to read from the coordinates? - A rectangle with the same base and area must have what height? - Its upper vertices lie directly above the base endpoints.

Solution

1. The vector from \(A\) to \(D\) is \((2, 4)\). Apply the same vector to \(B\): \(C=(8+2, 1+4)=(10, 5)\). 2. Base \(AB\) has length \(8-1=7\) units, and the height is \(5-1=4\) units. The area is \(7\times4=28\) square units. 3. The rectangle must also have height \(4\) units. Its upper vertices lie directly above \(A\) and \(B\) on \(y=5\), so \(D_1(1, 5)\) and \(C_1(8, 5)\).

Answer

a) \(C(10, 5)\); area \(28\) square units b) \(C_1(8, 5)\) and \(D_1(1, 5)\)
5121306
A trapezoid has vertices \(A(2, 1)\), \(B(10, 1)\), \(C(7, 5)\), and \(D(4, 5)\). Find its area in square units.

Hints

- Which sides of the quadrilateral are parallel? - Use the x-coordinates to find each horizontal side length. - Use the y-coordinates to find the perpendicular distance between the parallel sides.

Solution

1. The horizontal parallel sides have lengths \(10-2=8\) units and \(7-4=3\) units. 2. Their vertical distance is \(5-1=4\) units, so the height is \(4\) units. 3. The area is \(A=\frac{1}{2}(8+3)\times4=22\) square units.

Answer

The area of the trapezoid is \(22\) square units.
5188236
Rectangle \(ABCD\) has vertices \(A(2, 1)\), \(B(11, 1)\), \(C(11, 6)\), and \(D(2, 6)\). Find the distance between opposite sides \(\overline{AB}\) and \(\overline{CD}\), and the distance between opposite sides \(\overline{AD}\) and \(\overline{BC}\).

Hints

- Identify the horizontal and vertical sides. - The distance between one pair of opposite sides equals the length of the other pair. - Subtract the coordinates that differ.

Solution

1. Sides \(\overline{AB}\) and \(\overline{CD}\) lie on the horizontal lines \(y=1\) and \(y=6\). Their distance is \(6-1=5\) units. 2. Sides \(\overline{AD}\) and \(\overline{BC}\) lie on the vertical lines \(x=2\) and \(x=11\). Their distance is \(11-2=9\) units.

Answer

The distance between \(\overline{AB}\) and \(\overline{CD}\) is \(5\) units. The distance between \(\overline{AD}\) and \(\overline{BC}\) is \(9\) units.
5241526
Points \(P(2, 2)\), \(Q(7, 2)\), and \(R(2, 5)\) are connected in the order \(P-Q-R-P\). a) What type of polygon is formed? b) Explain without drawing why the polygon has a right angle. Name the vertex where the right angle is located.

Hints

- Compare the coordinates of \(P\) and \(Q\), and then compare the coordinates of \(P\) and \(R\). - Equal y-coordinates make a horizontal segment. - Equal x-coordinates make a vertical segment.

Solution

1. Connecting three distinct points forms a triangle. 2. Segment \(\overline{PQ}\) is horizontal because \(P\) and \(Q\) have the same y-coordinate. 3. Segment \(\overline{PR}\) is vertical because \(P\) and \(R\) have the same x-coordinate. 4. A horizontal segment and a vertical segment are perpendicular, so they form a right angle at their common endpoint, \(P\). Therefore, the polygon is a right triangle.

Answer

a) A right triangle is formed. b) \(\overline{PQ}\) is horizontal and \(\overline{PR}\) is vertical, so they are perpendicular. The right angle is at \(P\).
5321736
Three vertices of square \(PQRS\) are shown: \(P(3, 2)\), \(Q(-2, 2)\), and \(R(-2, -3)\). Segments \(\overline{PQ}\) and \(\overline{QR}\) are drawn. Find the coordinates of the fourth vertex \(S\).
Figure for problem 532173

Hints

- Count the grid units along the two drawn sides. - Opposite sides of a square are parallel. - The missing vertex lies directly below \(P\) and directly to the right of \(R\).

Solution

1. Segment \(\overline{PQ}\) is horizontal and has length \(3 - (-2) = 5\) units. 2. Segment \(\overline{QR}\) is vertical and has length \(2 - (-3) = 5\) units. 3. To complete the square, \(S\) must have the same x-coordinate as \(P\) and the same y-coordinate as \(R\). 4. Therefore, \(S = (3, -3)\).

Answer

\(S = (3, -3)\)
5371886
A nature preserve is triangular with vertices \(A(1, 1)\), \(B(7, 1)\), and \(C(4, 5)\). An observation post is planned at \(P(4, 2)\). Is the observation post inside or outside the preserve? Explain.
Figure for problem 537188

Hints

- Compare the point’s location with all three sides of the triangle. - Find the midpoint of the horizontal base. - Look for a segment from the base to vertex \(C\) that contains \(P\).

Solution

1. The midpoint of \(\overline{AB}\) is \(M(4, 1)\). 2. Segment \(\overline{MC}\) lies inside the triangle. 3. Point \(P(4, 2)\) lies on \(\overline{MC}\) because it has x-coordinate \(4\) and its y-coordinate is between \(1\) and \(5\). 4. Therefore, \(P\) lies inside the triangle.

Answer

Point \(P\) lies inside the nature preserve.
5109526
A parallelogram has vertices \(A(2, 2)\), \(B(2, 8)\), \(C(6, 11)\), and \(D(6, 5)\) on a coordinate plane where each unit represents \(1\,\text{cm}\). a) Find the area of the parallelogram using side \(AB\) as the base. b) A second parallelogram has vertices \(A(2, 2)\), \(B(2, 8)\), \(E(6, 13)\), and \(F(6, 7)\). Without recalculating the area, explain whether the second parallelogram has a greater area, a smaller area, or the same area as the first.

Hints

- Which side lies exactly on a vertical grid line? - How do you measure the height when the base is vertical? - Compare the base lengths and the distances between the opposite sides.

Solution

1. Side \(AB\) is vertical, so its length is \(8-2=6\,\text{cm}\). 2. The corresponding height is the horizontal distance between \(x=2\) and \(x=6\), which is \(6-2=4\,\text{cm}\). 3. The area is \(A=bh=6\times4=24\,\text{cm}^2\). 4. The second parallelogram has the same base \(AB\) and the same horizontal distance of \(4\,\text{cm}\) between its parallel sides. Therefore, it has the same area.

Answer

a) \(A=24\,\text{cm}^2\) b) The second parallelogram has the same area, \(24\,\text{cm}^2\), because its base and corresponding height are unchanged.
5109536
On a coordinate plane where each unit represents \(1\,\text{cm}\), the points \(P(1, 1)\), \(Q(11, 1)\), \(R(14, 5)\), and \(S(4, 5)\) form a parallelogram. a) Find the area \(A\) of the parallelogram. b) The slanted side \(QR\) is exactly \(5\,\text{cm}\) long. Find the corresponding height \(h_{QR}\), measured perpendicular to \(QR\). c) Explain why it may be difficult to measure \(h_{QR}\) exactly from a hand-drawn diagram, even when the diagram is drawn carefully.

Hints

- First find the area using the side whose length and height are easiest to read. - The area is the same no matter which side is chosen as the base. - Rearrange \(A=bh\) to solve for the height. - Think about the limits of a pencil, ruler, and right-angle construction.

Solution

1. Use horizontal side \(PQ\) as the base. Its length is \(11-1=10\,\text{cm}\), and the vertical height is \(5-1=4\,\text{cm}\). 2. The area is \(A=10\times4=40\,\text{cm}^2\). 3. Using side \(QR\) as the base, \(40=5\times h_{QR}\). Therefore, \(h_{QR}=40\div5=8\,\text{cm}\). 4. A hand-drawn diagram has limited precision because of line thickness, ruler markings, and small errors when constructing a perpendicular segment.

Answer

a) \(A=40\,\text{cm}^2\) b) \(h_{QR}=8\,\text{cm}\) c) Line thickness, ruler precision, and small construction errors can make a measured value slightly inaccurate.
5109816
The points \(A(2, 2)\), \(B(10, 2)\), \(C(12, 5)\), and \(D(4, 5)\) form a parallelogram. A triangle has vertices \(A\), \(B\), and \(E(6, 8)\). a) Find the area of parallelogram \(ABCD\). b) Find the area of triangle \(ABE\). c) Compare the areas. What do you notice about the bases and heights of the two figures?

Hints

- How do you find the length of a horizontal segment from its coordinates? - Recall the area formulas for a parallelogram and a triangle. - How do you find a height when the base is horizontal? - Compare the y-coordinates to find the perpendicular distances.

Solution

1. Segment \(AB\) has length \(10-2=8\) units. The parallelogram's height is \(5-2=3\) units, so its area is \(8\times3=24\) square units. 2. Triangle \(ABE\) has the same base, \(8\) units. Its height is \(8-2=6\) units, so its area is \(\frac{1}{2}\times8\times6=24\) square units. 3. The areas are equal. The triangle's height is twice the parallelogram's height, which offsets the factor \(\frac{1}{2}\) in the triangle area formula.

Answer

a) \(24\) square units b) \(24\) square units c) The areas are equal. The figures have the same base, and the triangle's height is twice the parallelogram's height.
5109966
Quadrilateral \(ABCD\) has vertices \(A(1, 2)\), \(B(5, 1)\), \(C(8, 4)\), and \(D(3, 6)\). Use a surrounding rectangle to find the quadrilateral's area. 1. Give the coordinates of the rectangle's vertices. 2. Find the rectangle's area. 3. Find the areas of the four right triangles outside \(ABCD\) but inside the rectangle. 4. Find the area of \(ABCD\).

Hints

- Use the least and greatest x- and y-coordinates to define the surrounding rectangle. - Find the leg lengths of each corner triangle by subtracting coordinates. - Subtract the four triangle areas from the rectangle's area.

Solution

1. The surrounding rectangle has vertices \((1, 1)\), \((8, 1)\), \((8, 6)\), and \((1, 6)\). 2. Its width is \(8-1=7\) units, and its height is \(6-1=5\) units. Its area is \(7\times5=35\) square units. 3. The four outside triangles have areas \(\frac{1}{2}\times4\times1=2\), \(\frac{1}{2}\times3\times3=4.5\), \(\frac{1}{2}\times5\times2=5\), and \(\frac{1}{2}\times2\times4=4\) square units. 4. Their total area is \(2+4.5+5+4=15.5\) square units, so the quadrilateral's area is \(35-15.5=19.5\) square units.

Answer

1. The rectangle's vertices are \((1, 1)\), \((8, 1)\), \((8, 6)\), and \((1, 6)\). 2. The rectangle's area is \(35\) square units. 3. The four triangle areas are \(2\), \(4.5\), \(5\), and \(4\) square units. 4. The area of \(ABCD\) is \(19.5\) square units.
5110806
Graph quadrilateral \(ABCD\) with vertices \(A(2, 1)\), \(B(10, 1)\), \(C(8, 5)\), and \(D(4, 5)\). Split the quadrilateral into a rectangle and two triangles to find its area. Briefly describe your decomposition.

Hints

- Graph the points and look for horizontal sides. - Draw vertical segments from the endpoints of the upper base to the lower base. - Add the areas of the resulting rectangle and two triangles.

Solution

1. Plot \(A(2, 1)\), \(B(10, 1)\), \(C(8, 5)\), and \(D(4, 5)\) and connect them in order. 2. The lower base \(AB\) has length \(10-2=8\) units, the upper base \(CD\) has length \(8-4=4\) units, and the height is \(5-1=4\) units. 3. Draw vertical segments from \(C\) and \(D\) to \(\overline{AB}\). This forms a central \(4\times4\) rectangle and two congruent side triangles. 4. The rectangle's area is \(4\times4=16\) square units. 5. Each side triangle has base \(2\) units and height \(4\) units, so each has area \(\frac{1}{2}\times2\times4=4\) square units. 6. The total area is \(16+4+4=24\) square units.

Answer

The graph can be split into a central \(4\times4\) rectangle and two congruent triangles, each with base \(2\) units and height \(4\) units. The area of quadrilateral \(ABCD\) is \(24\) square units.
5110816
Pentagon \(PQRST\) has vertices \(P(1, 2)\), \(Q(7, 2)\), \(R(9, 5)\), \(S(4, 8)\), and \(T(-1, 5)\). Find its area by splitting it into familiar figures.

Hints

- Look for two vertices that lie on the same horizontal line. - Use a horizontal segment to divide the pentagon. - Identify the triangle and trapezoid formed by the segment.

Solution

1. Draw horizontal segment \(\overline{TR}\) to split the pentagon into triangle \(TSR\) and trapezoid \(PQRT\). 2. For \(\triangle TSR\), the base is \(9-(-1)=10\) units and the height is \(8-5=3\) units. Its area is \(\frac{1}{2}\times10\times3=15\) square units. 3. The trapezoid has bases \(7-1=6\) units and \(10\) units and height \(5-2=3\) units. Its area is \(\frac{1}{2}(6+10)\times3=24\) square units. 4. The pentagon's area is \(15+24=39\) square units.

Answer

The area of pentagon \(PQRST\) is \(39\) square units.
5110826
Quadrilateral \(KLMN\) has vertices \(K(2, 2)\), \(L(8, 3)\), \(M(6, 7)\), and \(N(2, 5)\). Enclose it in a rectangle whose sides are parallel to the axes. Find the rectangle's area, then subtract the areas outside the quadrilateral to determine the area of \(KLMN\).

Hints

- Use the least and greatest coordinates to draw a surrounding rectangle. - Find the legs of each outside right triangle from coordinate differences. - Subtract the outside areas from the rectangle's area.

Solution

1. The surrounding rectangle extends from \(x=2\) to \(x=8\) and from \(y=2\) to \(y=7\). Its dimensions are \(6\times5\), so its area is \(30\) square units. 2. The lower-right triangle has area \(\frac{1}{2}\times6\times1=3\) square units. 3. The upper-right triangle has area \(\frac{1}{2}\times2\times4=4\) square units, and the upper-left triangle has area \(\frac{1}{2}\times4\times2=4\) square units. 4. No triangle must be removed at the lower-left corner because \(K\) is a corner of the rectangle and \(KN\) lies on its left side. 5. The quadrilateral's area is \(30-3-4-4=19\) square units.

Answer

The area of quadrilateral \(KLMN\) is \(19\) square units.
5110836
Triangle \(PQR\) has area \(12\,\text{cm}^2\). Points \(P(1, 1)\) and \(Q(1, 7)\) are given on a coordinate plane where each unit represents \(1\,\text{cm}\). a) Find the length of base \(PQ\). b) Find the required height of the triangle. c) On which two lines can point \(R\) lie? Give the equations of the lines and one possible point \(R\).

Hints

- How do you find the distance between two vertically aligned points? - Use the triangle area formula to find the height. - If the base is vertical, in which direction is its height measured? - Move the required distance to either side of the base line.

Solution

1. Since \(P\) and \(Q\) have the same x-coordinate, \(PQ=7-1=6\,\text{cm}\). 2. Use \(12=\frac{1}{2}\times6\times h\). This gives \(12=3h\), so \(h=4\,\text{cm}\). 3. The base lies on \(x=1\), so point \(R\) must have a horizontal distance of \(4\) units from that line. 4. Therefore, \(R\) lies on \(x=5\) or \(x=-3\). One possible point is \(R(5, 4)\).

Answer

a) \(PQ=6\,\text{cm}\) b) \(h=4\,\text{cm}\) c) \(R\) must lie on \(x=5\) or \(x=-3\). One possible point is \(R(5, 4)\).
5110846
Points \(A(-3, 0)\) and \(B(3, 0)\) are given. Triangle \(ABD\) has area \(18\) square units, and \(D\) has coordinates \((5, y)\). a) Find the y-coordinate of \(D\), given that \(y>0\). b) Explain why the x-coordinate of \(D\) does not affect the area as long as \(y\) stays the same.

Hints

- What is the length of base \(AB\)? - Use the triangle area formula. - What happens when a triangle's vertex moves parallel to its base? - Does a horizontal movement change the vertical distance to the x-axis?

Solution

1. Base \(AB\) has length \(3-(-3)=6\) units. 2. Use \(18=\frac{1}{2}\times6\times h\). This gives \(18=3h\), so \(h=6\) units. 3. Since \(AB\) lies on \(y=0\) and \(y>0\), the y-coordinate of \(D\) is \(6\). 4. Changing the x-coordinate moves \(D\) parallel to the horizontal base. The perpendicular distance to the base stays \(6\), so the area does not change.

Answer

a) \(y=6\) b) The x-coordinate only moves \(D\) parallel to the base. It does not change the height, so it does not change the area.
5110856
Points \(A(2, 2)\) and \(B(6, 2)\) form the common base of triangle \(ABC\) and parallelogram \(ABED\). Triangle \(ABC\) has area \(10\) square units. a) Find the triangle's height. b) Parallelogram \(ABED\) also has area \(10\) square units. On which horizontal line must side \(DE\) lie if it is above \(AB\)? c) Explain why the parallelogram's height differs from the triangle's height even though the figures have the same base and area.

Hints

- Compare the area formulas for triangles and parallelograms. - What factor appears only in the triangle formula? - After finding the parallelogram's height, add it to the base line's y-coordinate.

Solution

1. The base length is \(6-2=4\) units. 2. For the triangle, \(10=\frac{1}{2}\times4\times h_T=2h_T\), so \(h_T=5\) units. 3. For the parallelogram, \(10=4h_P\), so \(h_P=2.5\) units. 4. Since \(AB\) lies on \(y=2\), side \(DE\) must lie on \(y=2+2.5=4.5\). 5. The triangle formula includes \(\frac{1}{2}\), so with the same base and area, the triangle must be twice as high as the parallelogram.

Answer

a) \(5\) units b) \(y=4.5\) c) The triangle needs twice the height because its area formula includes the factor \(\frac{1}{2}\).
5115006
Triangle \(ABC\) has vertices \(A(2, 1)\), \(B(10, 1)\), and \(C(5, 7)\) on a coordinate plane where each unit represents \(1\,\text{cm}\). a) Find the area of triangle \(ABC\). b) Point \(C\) is moved along the line \(y=7\) to \(C_1(9, 7)\). How does the area change? Explain. c) Where could a point \(D\) lie so that triangle \(ABD\) has twice the area of triangle \(ABC\)? Give one possible coordinate.

Hints

- Choose the side parallel to an axis as the base. - Find the vertical distance from the third vertex to the horizontal base. - What changes when the vertex moves parallel to the base? - With the base fixed, how must the height change to double the area?

Solution

1. Base \(AB\) has length \(10-2=8\,\text{cm}\), and the height is \(7-1=6\,\text{cm}\). 2. The area is \(A=\frac{1}{2}\times8\times6=24\,\text{cm}^2\). 3. Moving \(C\) to \(C_1\) does not change its y-coordinate, so the height and area stay the same. 4. Twice the original area is \(48\,\text{cm}^2\). With the same base, the required height is \(12\,\text{cm}\). 5. Since \(AB\) lies on \(y=1\), point \(D\) may lie on \(y=13\) or \(y=-11\). One possible point is \(D(5, 13)\).

Answer

a) \(24\,\text{cm}^2\) b) The area stays \(24\,\text{cm}^2\). c) One possible point is \(D(5, 13)\). Any point on \(y=13\) or \(y=-11\) works.
5115026
Parallelogram \(ABCD\) has vertices \(A(1, 1)\), \(B(7, 1)\), \(C(9, 5)\), and \(D(3, 5)\). a) Find the area of the parallelogram. b) Point \(P(5, 5)\) lies on side \(CD\). Find the area of triangle \(ABP\). c) Compare the two areas. Does the same relationship hold for every point \(P\) on segment \(CD\)?

Hints

- Compare the area formulas for a parallelogram and a triangle. - What base and height do the two figures share? - Does moving \(P\) along \(CD\) change its perpendicular distance from \(AB\)?

Solution

1. Base \(AB\) has length \(7-1=6\) units, and the parallelogram's height is \(5-1=4\) units. Its area is \(6\times4=24\) square units. 2. Triangle \(ABP\) has the same \(6\)-unit base and the same \(4\)-unit height. Its area is \(\frac{1}{2}\times6\times4=12\) square units. 3. The triangle has one-half the parallelogram's area. Every point on \(CD\) is the same perpendicular distance from \(AB\), so the relationship holds for every such point.

Answer

a) \(24\) square units b) \(12\) square units c) The triangle has one-half the parallelogram's area. This is true for every point \(P\) on \(CD\).
5191366
Points \(A(3, 2)\), \(B(8, 2)\), and \(C(5, 6)\) are given in the coordinate plane. a) Find the distance from \(C\) to the line through \(A\) and \(B\). b) A line through \(C\) is parallel to \(\overline{AB}\). A line through \(A\) is parallel to \(\overline{BC}\). Find the coordinates of their intersection.

Hints

- First determine the direction of \(\overline{AB}\). - A parallel line has the same direction. - Use the horizontal and vertical changes from \(B\) to \(C\), then apply them from \(A\).

Solution

1. Line \(\overleftrightarrow{AB}\) is horizontal with equation \(y=2\). The distance from \(C(5,6)\) to this line is \(6-2=4\) units. 2. The line through \(C\) parallel to \(\overline{AB}\) has equation \(y=6\). 3. From \(B\) to \(C\), the change is \(3\) units left and \(4\) units up. Applying the same change to \(A(3,2)\) gives \((3-3,2+4)=(0,6)\). 4. The point \((0,6)\) lies on both requested lines, so it is their intersection.

Answer

a) \(4\) units b) \((0, 6)\)
5191416
Points \(A(2, 2)\), \(B(7, 2)\), and \(C(7, 5)\) are given. a) Find the coordinates of point \(D\) so that \(ABCD\) is a rectangle. b) Keep points \(A\) and \(B\) and all x-coordinates unchanged. Keep \(C\) and \(D\) above \(\overline{AB}\). What must the y-coordinates of \(C\) and \(D\) be so that \(ABCD\) is a square?

Hints

- Compare the x- and y-coordinates of adjacent rectangle vertices. - Use matching x- and y-coordinates to complete the rectangle. - Find the length of the horizontal side. - A square has four congruent sides.

Solution

1. For \(ABCD\) to be a rectangle, \(D\) must have the same x-coordinate as \(A\) and the same y-coordinate as \(C\). Therefore, \(D(2, 5)\). 2. The horizontal side length is \(AB = 7 - 2 = 5\) units. 3. For a square, the vertical side length must also be \(5\) units. Starting from \(y = 2\), the upper vertices must have y-coordinate \(2 + 5 = 7\). 4. Therefore, the new points are \(C(7, 7)\) and \(D(2, 7)\).

Answer

a) \(D(2, 5)\) b) The y-coordinate of both \(C\) and \(D\) must be \(7\).
5191426
Points \(E(1, 1)\), \(F(6, 1)\), and \(G(8, 4)\) are given on a coordinate plane. a) Find the coordinates of point \(H\) so that \(EFGH\) is a parallelogram. b) Find a different point \(H_2\) so that \(EFGH_2\) is a trapezoid but not a parallelogram.

Hints

- Compare the direction and length of \(\overline{EF}\) with those of \(\overline{HG}\). - Use coordinate differences to find a horizontal segment’s length. - A trapezoid needs at least one pair of parallel sides. - Part b has more than one possible answer.

Solution

1. Segment \(\overline{EF}\) is horizontal and has length \(6 - 1 = 5\) units. 2. For a parallelogram, \(\overline{HG}\) must be parallel and congruent to \(\overline{EF}\). Moving \(5\) units left from \(G(8, 4)\) gives \(H(3, 4)\). 3. For a trapezoid that is not a parallelogram, one pair of opposite sides can be parallel without being congruent. One choice is \(H_2(5, 4)\). Then \(\overline{H_2G}\) is horizontal and parallel to \(\overline{EF}\), but the other pair of opposite sides is not parallel.

Answer

a) \(H(3, 4)\) b) One possible answer is \(H_2(5, 4)\).
5200046
Rectangle \(ABCD\) has opposite vertices \(A(2, 1)\) and \(C(9, 6)\). Its sides are parallel to the coordinate axes. a) Find the coordinates of \(B\) and \(D\) without drawing the rectangle. b) Find the two different side lengths of the rectangle.

Hints

- Adjacent vertices on a horizontal or vertical side share one coordinate. - Match the x-coordinate from one opposite vertex with the y-coordinate from the other. - For horizontal or vertical segments, subtract the changing coordinates.

Solution

1. Point \(B\) shares the x-coordinate of \(C\) and the y-coordinate of \(A\), so \(B = (9, 1)\). 2. Point \(D\) shares the x-coordinate of \(A\) and the y-coordinate of \(C\), so \(D = (2, 6)\). 3. The horizontal side length is \(9 - 2 = 7\) units. 4. The vertical side length is \(6 - 1 = 5\) units.

Answer

a) \(B = (9, 1)\) and \(D = (2, 6)\) b) The side lengths are \(7\) units and \(5\) units.
5200056
Points \(P(3, 5)\) and \(Q(10, 8)\) are endpoints of one side of parallelogram \(PQRS\). Sides \(\overline{PS}\) and \(\overline{QR}\) are parallel to the y-axis and each has length \(4\) units. Give the coordinates of \(R\) and \(S\) for two different possible parallelograms.

Hints

- Vertical segments have endpoints with the same x-coordinate. - A vertical segment of length \(4\) can extend up or down. - Apply the same vertical change to both given points.

Solution

1. Because \(\overline{PS}\) and \(\overline{QR}\) are vertical, \(S\) has x-coordinate \(3\), and \(R\) has x-coordinate \(10\). 2. One possibility is to move both points up \(4\) units. Then \(S = (3, 9)\) and \(R = (10, 12)\). 3. A second possibility is to move both points down \(4\) units. Then \(S = (3, 1)\) and \(R = (10, 4)\).

Answer

One possibility: \(R = (10, 12)\) and \(S = (3, 9)\) Another possibility: \(R = (10, 4)\) and \(S = (3, 1)\)
5200066
In parallelogram \(ABCD\), the vertices \(A(1, 2)\), \(B(8, 2)\), and \(D(3, 6)\) are given. a) Find the length of \(\overline{AB}\). b) Find the coordinates of \(C\) without drawing. Briefly explain your method.

Hints

- Compare the coordinates of \(A\) and \(B\). - Opposite sides of a parallelogram are parallel and equal in length. - Apply the movement from \(A\) to \(B\) starting at \(D\).

Solution

1. Points \(A\) and \(B\) have the same y-coordinate, so \(\overline{AB}\) is horizontal. Its length is \(8 - 1 = 7\) units. 2. Opposite sides of a parallelogram are parallel and equal in length. Therefore, \(\overline{DC}\) is horizontal and has length \(7\). 3. Starting at \(D(3, 6)\), move \(7\) units right to get \(C = (10, 6)\).

Answer

a) \(7\) units b) \(C = (10, 6)\). Moving from \(A\) to \(B\) is \(7\) units right, so move \(7\) units right from \(D\).
5241536
A square in the coordinate plane has vertices \(A(2, 1.5)\), \(B(5.5, 1.5)\), and \(C(5.5, 5)\), listed in order around the square. a) Find the coordinates of the fourth vertex \(D\). b) Find the side length of the square in grid units.

Hints

- Which vertices must line up horizontally and vertically? - All four sides of a square have the same length. - Subtract the corresponding coordinates of adjacent vertices.

Solution

1. Point \(D\) must have the same x-coordinate as \(A\) and the same y-coordinate as \(C\). Therefore, \(D = (2, 5)\). 2. The horizontal side length is \(5.5 - 2 = 3.5\) units. 3. The vertical side length is \(5 - 1.5 = 3.5\) units, confirming that the figure is a square.

Answer

a) \(D = (2, 5)\) b) The side length is \(3.5\) grid units.
5241676
Points \(A(2, 1)\), \(B(7, 1)\), and \(C(7, 4)\) are vertices of an axis-aligned rectangle. One coordinate unit represents \(1\,\text{cm}\). a) Find point \(D\) so that \(ABCD\) is the rectangle. b) Find the area of the rectangle.

Hints

- Opposite sides of a rectangle are parallel. - Use coordinate differences to find the side lengths. - Recall the area formula for a rectangle.

Solution

1. To complete the axis-aligned rectangle, \(D\) must share the x-coordinate of \(A\) and the y-coordinate of \(C\). Thus, \(D = (2, 4)\). 2. The length is \(7 - 2 = 5\,\text{cm}\), and the width is \(4 - 1 = 3\,\text{cm}\). 3. The area is \(5\,\text{cm} \times 3\,\text{cm} = 15\,\text{cm}^2\).

Answer

a) \(D = (2, 4)\) b) \(15\,\text{cm}^2\)
5321746
Three consecutive vertices of rectangle \(ABCD\) are shown: \(A(2, 1)\), \(B(6, 3)\), and \(C(5, 5)\). Find the coordinates of the missing vertex \(D\).
Figure for problem 532174

Hints

- Opposite sides of a rectangle have the same direction and length. - Determine the horizontal and vertical change from \(B\) to \(C\). - Apply that same change to \(A\).

Solution

1. From \(B(6, 3)\) to \(C(5, 5)\), the coordinate change is \((-1, 2)\). 2. Opposite sides of a rectangle are parallel and equal, so the change from \(A\) to \(D\) is also \((-1, 2)\). 3. Apply this change to \(A(2, 1)\): \(D = (2 - 1, 1 + 2) = (1, 3)\).

Answer

\(D = (1, 3)\)
5322046
Points \(A\), \(B\), and \(C\) form three consecutive vertices of an incomplete rectangle \(ABCD\). a) Read the coordinates of \(A\), \(B\), and \(C\) from the graph. b) Find the coordinates of the missing vertex \(D\). c) One grid unit represents \(1\,\text{cm}\). Find the perimeter of rectangle \(ABCD\).
Figure for problem 532204

Hints

- Read the x-coordinate before the y-coordinate. - Opposite sides of a rectangle are parallel and equal. - Find the two side lengths before using the perimeter formula.

Solution

1. Reading the graph gives \(A = (-2, -3)\), \(B = (4, -3)\), and \(C = (4, 1)\). 2. Point \(D\) must share the x-coordinate of \(A\) and the y-coordinate of \(C\), so \(D = (-2, 1)\). 3. The side lengths are \(4 - (-2) = 6\,\text{cm}\) and \(1 - (-3) = 4\,\text{cm}\). 4. The perimeter is \(2(6 + 4) = 20\,\text{cm}\).

Answer

a) \(A = (-2, -3)\), \(B = (4, -3)\), \(C = (4, 1)\) b) \(D = (-2, 1)\) c) \(20\,\text{cm}\)
5331706
Three consecutive vertices of square \(ABCD\) are shown: \(A(3, 2)\), \(B(8, 3)\), and \(C(7, 8)\). Find the coordinates of the missing vertex \(D\).
Figure for problem 533170

Hints

- Determine the coordinate change from one endpoint of a side to the other. - Opposite sides of a square are parallel and equal. - Apply the same coordinate change to the opposite vertex.

Solution

1. The coordinate change from \(B\) to \(A\) is \((-5, -1)\). 2. Opposite sides of a square are parallel and equal, so the same coordinate change takes \(C\) to \(D\). 3. Apply the change to \(C(7, 8)\): \(D = (7 - 5, 8 - 1) = (2, 7)\).

Answer

\(D = (2, 7)\)
5331716
An animal enclosure is shaped like parallelogram \(EFGH\). Three fence posts are at \(E(1, 1)\), \(F(6, 2)\), and \(H(2, 5)\). Find the coordinates where the fourth post \(G\) must be placed.
Figure for problem 533171

Hints

- Opposite sides of a parallelogram are parallel and equal. - Find the horizontal and vertical change from \(E\) to \(F\). - Apply that change starting at \(H\).

Solution

1. From \(E(1, 1)\) to \(F(6, 2)\), the coordinate change is \((5, 1)\). 2. Opposite sides of a parallelogram are parallel and equal, so the same change takes \(H\) to \(G\). 3. Apply the change to \(H(2, 5)\): \(G = (2 + 5, 5 + 1) = (7, 6)\).

Answer

\(G = (7, 6)\)
5349016
The vertices of quadrilateral \(ABCD\) are shown on a coordinate plane. a) Find the coordinates of \(A\), \(B\), \(C\), and \(D\). b) Classify the quadrilateral.
Figure for problem 534901

Hints

- Read the x-coordinate before the y-coordinate. - Compare the horizontal and vertical side lengths. - Use the side directions and angle types to classify the quadrilateral.

Solution

1. Reading the graph gives \(A(-4, -1)\), \(B(3, -1)\), \(C(3, 2)\), and \(D(-4, 2)\). 2. The horizontal sides each have length \(3 - (-4) = 7\) units, and the vertical sides each have length \(2 - (-1) = 3\) units. 3. Adjacent sides are horizontal and vertical, so all four angles are right angles. Therefore, \(ABCD\) is a rectangle.

Answer

a) \(A(-4, -1)\), \(B(3, -1)\), \(C(3, 2)\), and \(D(-4, 2)\) b) A rectangle
5369026
Use coordinates to determine whether the quadrilateral with vertices \(A(1, 1)\), \(B(6, 1)\), \(C(8, 4)\), and \(D(3, 4)\) is a parallelogram.
Figure for problem 536902

Hints

- Compare the coordinate changes from \(A\) to \(B\) with those from \(D\) to \(C\). - One pair of opposite sides that is both parallel and congruent is enough to prove a quadrilateral is a parallelogram.

Solution

1. From \(A(1, 1)\) to \(B(6, 1)\), the horizontal change is \(5\) and the vertical change is \(0\). 2. From \(D(3, 4)\) to \(C(8, 4)\), the horizontal change is also \(5\) and the vertical change is \(0\). 3. Therefore, \(\overline{AB}\) and \(\overline{DC}\) have the same length and direction. One pair of opposite sides is both parallel and congruent, so \(ABCD\) is a parallelogram.

Answer

Yes. Both \(\overline{AB}\) and \(\overline{DC}\) move \(5\) units right and \(0\) units vertically, so the quadrilateral is a parallelogram.
5371896
Quadrilateral \(ABCD\) has vertices \(A(2, 1)\), \(B(8, 1)\), \(C(7, 5)\), and \(D(3, 5)\). Determine whether point \(Q(8, 3)\) lies inside or outside the quadrilateral.
Figure for problem 537189

Hints

- Examine the slanted right side \(\overline{BC}\). - Find the point on \(\overline{BC}\) whose y-coordinate is \(3\). - Compare its x-coordinate with the x-coordinate of \(Q\).

Solution

1. The right boundary is segment \(\overline{BC}\), from \(B(8, 1)\) to \(C(7, 5)\). 2. Halfway in y from \(1\) to \(5\), at \(y = 3\), the x-coordinate on \(\overline{BC}\) is halfway from \(8\) to \(7\), which is \(7.5\). 3. Point \(Q\) has coordinates \((8, 3)\), so it lies to the right of the boundary at the same y-coordinate. 4. Therefore, \(Q\) lies outside the quadrilateral.

Answer

Point \(Q\) lies outside the quadrilateral.
5109826
A triangle on the coordinate plane has vertices \(A(-5, 5)\), \(B(5, 5)\), and \(C(-5, -5)\). a) Graph the triangle and find its total area. b) What percent of the triangle's total area lies in Quadrant I?

Hints

- Graph the axes and identify Quadrant I. - Determine where the triangle meets the x-axis and y-axis. - Identify the shape of the portion in Quadrant I. - Find the total area and the Quadrant I area separately.

Solution

1. Plot \(A(-5, 5)\), \(B(5, 5)\), and \(C(-5, -5)\) and connect the points to form the triangle. 2. Segments \(AB\) and \(AC\) are perpendicular and each has length \(10\) units. Therefore, the triangle's total area is \(\frac{1}{2}\times10\times10=50\) square units. 3. Segment \(BC\) lies on \(y=x\), so it passes through \((0, 0)\). The part in Quadrant I is a right triangle with vertices \((0, 0)\), \((0, 5)\), and \((5, 5)\). 4. That smaller triangle has area \(\frac{1}{2}\times5\times5=12.5\) square units. 5. The percent is \(\frac{12.5}{50}\times100\%=25\%\).

Answer

a) Plot \(A(-5, 5)\), \(B(5, 5)\), and \(C(-5, -5)\) and connect them. The total area is \(50\) square units. b) \(25\%\) of the area lies in Quadrant I.
5109986
Triangle \(XYZ\) has vertices \(X(2, 2)\), \(Y(10, 4)\), and \(Z(5, 9)\). None of its sides is horizontal or vertical. Find its exact area without measuring any lengths. Explain how a surrounding rectangle can be used.

Hints

- Enclose the triangle in a rectangle whose sides are parallel to the axes. - Identify the three right triangles outside \(XYZ\). - Use coordinate differences to find the legs of those triangles.

Solution

1. Enclose the triangle in the rectangle with vertices \((2, 2)\), \((10, 2)\), \((10, 9)\), and \((2, 9)\). 2. The rectangle has area \((10-2)\times(9-2)=8\times7=56\) square units. 3. The three outside right triangles have areas \(\frac{1}{2}\times8\times2=8\), \(\frac{1}{2}\times5\times5=12.5\), and \(\frac{1}{2}\times3\times7=10.5\) square units. 4. Subtract their areas from the rectangle: \(56-(8+12.5+10.5)=25\) square units.

Answer

The exact area of triangle \(XYZ\) is \(25\) square units.

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