Answer :
Cross section is the area you make when you make a cut across a shape. In this case, the cut must be parallel to the base. Hence, the cut shape would be same to that of the base. The base's dimensions are 7 cm long x 5 cm wide. Thus, the cross section area is 35 square centimeters.
20 square centimeters, 28 square centimeters, and 35 square centimeters.