Answer:
Volume = 516.1425 cubic feet
Explanation:
The pentagon base appears regular. so every side is 10 feet in length.
Now we need to figure out the area of the pentagonal base in order to find volume.
Volume V = (pentagon base area)*height
I need to find the apothem length as indicated in the drawing.
call it "a"
360/5 = 72 degrees.
36 degrees.
5/a = tan 36 , a = 5/(tan 36) = 6.88190 feet.
Area of pentagon base = 5 * (1/2)*10* a = 5*(1/2)*10* 6.88190 =172.0475 sq. ft
Area of pentagon base = =172.0475 sq. ft
V = 172.0475 * 3 = 516.1425 cubic feet