We are given that 4 units = 320 ft. This implies that 1 unit = 80 ft. We count the other base to be 9 units = 720 ft, and the height to be 5 units = 400 ft. Using the formula for the area of a trapezoid, [tex] \frac{400(320+720)}{2}=208,000 [/tex], which is C