Question

There is a frustum of a regular square pyramid for which "h" is the height, "a" is the length of a side of the lower base, "b" is the length of a side of the upper base, and "l" is the slant height. What is the area of its lower base?

Answer 1

area of lower base since its a square is a^2
upper base would be b^2
area of sides would be like trapezoids
->each side area = (1/2)*l*(a+b)