Mariko has a bedroom wall that is shaped like a trapezoid with a height of 8 ft, a top base of 10 ft, and a bottom base of 13 ft. In the middle of this wall is a circular window whose radius is 2 ft. What is the area of the wall without the window? Use 3.14 for pi.

First, you have to find the area of the entire wall, including the window. The formula for the area of a trapezoid is:

A = (b1 + b2) / 2 * h

b1 is the first base, b2 is the second base, A is the total area, and h is the height.

Plug in the numbers from the problem.

(13 + 10) / 2 * 8

Simplify.

(23) / 2*8

11.5*8 = 92

Now, to calculate the window's surface area, you use the formula for area of a circle.

A = 3.14*r^2

Plug in your number.

A = 3.14 * 2^2

Simplify.

A = 3.14 * 4

A = 12.56

Now, you subtract the area of the window from the total area of the wall.

92 - 12.56 = 79.44

79.44 feet