In the triangle ABC, the area of BDE, DCE and ACD are 90, 30 and 28 square centimeters respectively?
Because s △ BDE = 90 square centimeter, s △ DCE = 30 square centimeter, be: EC = 90:30 = 3:1, and s △ ABC = 90 + 30 + 28 = 148 square centimeter, the area of triangle Abe is 148 × 33 + 1 = 111 (square centimeter), and the area of triangle ade is 111-90 = 21 (square centimeter). A: the area product of triangle ade is 21 square centimeter