Explanation:
step 1. this is a trapezoid. the area A = (b1 + b2)h/2 where b1 is the bottom base and b2 is the top base (per se), and h is the height. this formula is the definition of the area of a trapezoid.
step 2. A = (b1 + b2)h/2 = (22 + 9)(5)/2
step 3. A = 31(5)/2 = 155/2 = 77.5in^2.