7.4 areas of triangles and quadrilaterals warm-up (in) 1. find the side length of an equilateral...
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7.4 Areas of Triangles and Quadrilaterals
Warm-up (IN)1. Find the side length of an equilateral triangle
with perimeter 15.2. Find the side length of a square with
perimeter 36.3. Find the lengths of the legs of an isosceles
triangle with base 12 and perimeter 28.4. Find the lengths of the other sides of a
parallelogram with one side 4 and perimeter 40.
5. Find the height of an equilateral triangle whose sides are 5 units long.
Learning Objective: To find the areas of triangles and quadrilaterals and use the formulas in real world applications
9
5
8
4, 16, 16
About 4.3 units
s
Notes
Learning Objective: To find the areas of triangles and quadrilaterals and use the formulas in real world applications
Area Formulas
Rectangle
2sA
b
hbhA
Square Triangle
b
h
Parallelogram
bhA2
1
b
h bhA
Trapezoid
1b
2b
h
hbbA 212
1
Learning Objective: To find the areas of triangles and quadrilaterals and use the formulas in real world applications
EX 1 – Find the area of an isosceles trapezoid with perimeter 48 in. if the lengths of the bases are 14 in. and 18in.
14
182 2
181448 16
8 822 2h 28
4 2h 642h 60h 152
hbbA 212
1
2
1A 14 18 152
2
1A 32 152
61A 152
1532A 94.123 2in
Learning Objective: To find the areas of triangles and quadrilaterals and use the formulas in real world applications
EX 2 – Find the area of the parallelogram5 ft
13 ft
yd3
17
2132h25
25 2h 1692h 144h 12
bhAydyd
3
22
3
17
yd
ft
1
3 ft22
A 22 12A 2264 ft
CKC p. 363!! On separate paper!
HW – p. 364 #1-7, 10-13, 17-21 odd
Out – The sides of 2 parallelograms are congruent. Must their areas be the same? Explain.
Summary – Today, I learned…POW!!