10-4 notes and answers.notebookimages.pcmac.org/sisfiles/schools/al/madisoncity/bjhigh... · 2019....
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104 Notes and answers.notebook
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November 07, 2013
Nov 62:57 PM
Find the perimeters and areas of figures in a coordinate plane.
Objective
Nov 62:57 PM
Remember!
104 Notes and answers.notebook
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November 07, 2013
Nov 62:57 PM
Draw and classify the polygon with vertices E(–1, –1), F(2, –2), G(–1, –4), and H(–4, –3). Find the perimeter and area of the polygon.
Example 2: Finding Perimeter and Area in the Coordinate Plane
EFGH appears to be a parallelogram. To verify this, use slopes to show that opposite sides are parallel.
slope of EF =
slope of FG =
slope of GH =
slope of HE =
The opposite sides are parallel since their slopes are equal so EFGH is a parallelogram.
Nov 62:57 PM
Example 2 Continued
Since EFGH is a parallelogram, EF = GH, and FG = HE.
Use the Distance Formula to find each
perimeter of EFGH:
E(1, 1), F(2, 2), G(1, 4), and H(4, 3)
104 Notes and answers.notebook
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November 07, 2013
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Example 2 Continued
To find the area of EFGH, draw a line to divide EFGH into two triangles. The base and height of each triangle is 3. The area of each triangle is
The area of EFGH is 2(4.5) = 9 units2.
Nov 62:57 PM
Check It Out! Example 2
Draw and classify the polygon with vertices H(–3, 4), J(2, 6), K(2, 1), and L(–3, –1). Find the perimeter and area of the polygon.
HJKL appears to be a parallelogram. To verify this, use slopes to show that opposite sides are parallel.
are vertical lines.
The opposite sides are parallel since their slopes are equal, so HJKL is a parallelogram.
104 Notes and answers.notebook
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November 07, 2013
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Since HJKL is a parallelogram, HJ = KL, and JK = LH.
Use the Distance Formula to find each
perimeter of EFGH:
Check It Out! Example 2 Continued (3, 4), J(2, 6), K(2, 1), and L(3, 1)
Nov 62:57 PM
Check It Out! Example 2 Continued
To find the area of HJKL, draw a line to divide HJKL into two triangles. The base and height of each triangle is 3. The area of each triangle is
The area of HJKL is 2(12.5) = 25 units2.
104 Notes and answers.notebook
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November 07, 2013
Nov 63:49 PM
See Example 2 on page 705.
Nov 62:57 PM
Find the area of the polygon with vertices A(–4, 1), B(2, 4), C(4, 1), and D(–2, –2).
Example 3: Finding Areas in the Coordinate Plane by Subtracting
104 Notes and answers.notebook
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November 07, 2013
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Check It Out! Example 3 Find the area of the polygon with vertices K(–2, 4), L(6, –2), M(4, –4), and N(–6, –2).
Draw the polygon and close it in a rectangle.
Area of rectangle:A = bh = 12(8)= 96 units2.
Nov 62:57 PM
Check It Out! Example 3 Continued
Area of triangles:
a b
d c
The area of the polygon is 96 – 12 – 24 – 2 – 10 = 48 units2.
104 Notes and answers.notebook
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November 07, 2013
Nov 63:14 PM
Assignment(p. 697) 2, 3, 10, 11, 13, 18, 20(p. 707) 6, 8 and Draw and classify the polygon with vertices L(2, 1), M(2, 3), N(0, 3), and P(1, 0). Find the perimeter and area of the polygon.