Friday, April 20, 2007

Problem Solving - 20

What is the area of the trapezoid pictured to the right?

(A) 22.5

(B) 24

(C) 27

(D) 45

(E) 54


Answer: A

Since the triangle is a right isosceles triangle, the other side of the triangle (the height of the trapezoid) must also be 3. The top base if the trapezoid must be 6 since it is the opposite side of a rectangle.

The area of a trapezoid = 1/2 (sum of parallel sides) × (distance between the parallel sides)
= 1/2 (9 + 6) (3) = 22.5

The area can also be found here by breaking up the figure into a rectangle (area of 6 × 3 = 18) and a triangle (area of ½ × 3 × 3 = 4.5) and adding these two areas.


The correct answer is A.