1. Triangles and Parallelograms Lesson 11.2

2. Theorem 100: The area of a parallelogram is equal to the product of the base and the height.
A = bh h b M T H
13cm
9cm
6cm A
Find the area of MATH

3. M T H
13cm
9cm
6cm A
You will receive one point for each line, plus the correct unit. Minimum 3 lines.
A = bh
= 13(6)
= 78cm2

4. Theorem 101: The area of a triangle is equal to one-half the product of a base and the height (or altitude) for that base.
A = bh
Where b is the length of the base and h is the altitude. Altitude may be inside, outside or the leg of the triangle. The base may not always be at the bottom. h b

5. Find the area of this triangle.
12mm
8mm
A = 48 mm2 x 15
Find the base of a triangle with an altitude of 15 and area 60.
x = 8

6. How will you find the height?
Find the area of a parallelogram whose sides are 14 and 6 and whose acute angle is 60˚. Draw and label. D 6 14
60˚ U C K 6
How will you find the height?

7. Drop line DS to form a 30-60-90 triangle. Line DS is14
60˚ U C K S
Drop line DS to form a triangle.
Line DS is
A = bh
= 14( )
= 42

8. Team Activity:
Draw a parallelogram that has a perimeter of 40 units .
What is its area?
Which team created the parallelogram with the GREATEST area?
What shape is it?