Question

Composite Figures!
MEDALS REWARDED!!

Answer 1

Your car's back window is in the shape of a trapezoid with the dimensions shown. The 16-inch window wiper cleans a part of the window in a semicircular pattern. What is the approximate area of the window that is NOT cleaned by the wiper?

Answer 2

A) about 3.8
B) about 398
C) about 402
D) about 800

Answer 3

@topanga
Because I have the right too...

Answer 4

Remember it's NOT

Answer 5

Semicircle area = circle area / 2 = (pi*r^2)/2
16 in is the radius. Let's call the area of this semicircle s.
3.14*16^2=s

Trapezoid area = ((base 1 + base 2) / 2) * h
Here, base 1 is 44 and base 2 is 36. The height (h) is 20. Let's call this trapezoid's area t.
(44+36)/2 *20 = t

We can remove the area of the semicircle (that created by the windshield wiper) by subtracting it from the area of the trapezoid.
t - s = uncleaned area
[(44+36)/2 * 20] - [3.14 * 16^2] = uncleaned area

Remember the order of operations to be sure you don't make silly mistakes.

Answer 6

Okay thanks!

Answer 7

Thanks! :D