Answer:
920 feet
just multiply the length by the height on each side. For example 8 X 15= 120 then divide that number by two because it is a triangle.
Step-by-step explanation:
surface area = 2(1/2 * 15 * 8) + 20(17 + 8 + 15)
= 120 + 800
= 920 ft²
