Question

HELP. TODD.

Kristine has a bedroom wall that is shaped like a trapezoid with a height of 9 ft, a top base of 12 ft, and a bottom base of 15 ft. In the middle of this wall is a circular window whose radius is 3 ft.

What is the area of the wall without the window?

Use 3.14 for pi.

Enter your answer in the box.

Answer 1

First, we figure out the area of the wall, which is shaped like a trapezoid. The equation for the area of a trapezoid is 
$\frac{1}{2} (a+b)h$
where a is the top base, b is the bottom base and h is the height.
Substitute your given values into the equation and solve:
A=1/2(12+15)9
A=4.5(27)
Area of the wall= 121.5ft²

Now we figure out the area of the of the circular window. The formula for the area of a circle is 
$\pi r^{2}$
where r is the radius
Substitute your given values into the equation and solve:
pi×3²
$9 \pi =28.27433388 ft^{2}$

Now finally minus the area of the window from the area of the wall.
121.5-28.27433388=93.22566612
To 1 d.p., the area of the wall without the window is 93.2ft²