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11.2 Areas of Parallelograms and Triangles. Objective: After studying this section you will be able to find the areas of parallelograms and triangles. height (h). base (b). The Area of a Parallelogram. We can “cut and paste” to find the area of a parallelogram. cut. paste. =.
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11.2 Areas of Parallelograms and Triangles Objective: After studying this section you will be able to find the areas of parallelograms and triangles
height (h) base (b) The Area of a Parallelogram We can “cut and paste” to find the area of a parallelogram. cut paste =
Theorem 100 The area of a parallelogram is equal to the product of the base and the height for that base. where b is the length of the base and h is the height
The Area of a Triangle The area of any triangle can be shown to be one half of the area of a parallelogram with the same base and height 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. where b is the length of the base and h is the altitude.
Example 1 Find the area of the triangle 15 cm 10 cm Example 2 8 mm 3 mm
Example 3 Find the base of a triangle with altitude 15 and area 60. (Hint: draw a picture) Example 4 Find the area of a parallelogram whose sides are 14 and 6 and whose acute angle is 60 degrees. (Hint: draw a picture).
Example 5 Find the area of trapezoid (use formulas you learned in this lesson). 12 13 15 18
Summary State in your own words how you can find the area of a parallelogram and a triangle. Homework: worksheet