Question

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 1

The answer is 337.88 in2

Answer 2

338 squared inches is the approximate area of the window that is not cleaned by the wiper.

Explanation:

Area of trapezoid shaped widow: A

Length of the longer side of window= a = 42 inches

Another length of window = b = 32 inches

height of the window = h = 20 inch

Area of trapezoid =
`((a+b))/(2)* h`

`A=(42 inch+32 inch)/(2)* 20 inch`

`A=740 inch^2`

Area of the semicircle = A'

Radius of the circle = r = 16 inch

Area of the semi-circle =
`(1)/(2)\pi r^2`

`A'=(1)/(2)* 3.14* (16 inch)^2=402.12 inch^2`

Area of the window left uncleaned :

= A - A' =
`740 inch^2-402.12 inch^2=337.88 inch^2\approx 338 inch^2`

338 squared inches is the approximate area of the window that is not cleaned by the wiper.