Stu is making a stained glass window in the shape of a regular pentagon. the pentagon can be divided into congruent triangles each with a base of 8.7 inches and a height of 6 inches. what is the area of the window

The regular pentagon has five sides equal. If this divided into five triangles and we can solve the area of the triangle, then we can solve for the area of the regular pentagon.
The solution is shown below:
Area triangle = 1/2*base*height
base = 8.7 inches
height = 6 inches
Area triangle = 1/2*8.7 *6 = 26.10 in² 

We can solve now for the area of the regular polygon such as shown below:
Area regular pentagon = 5 * 26.10
Area regular pentagon = 130.5 in²

The answer is 130.5 inches².