Area of a parallelogram=base×corresponding height
In the first parallelogram, AB = 16 cm, AE = 8 cm and CF = 10 cm.
Area = b × h = AB × AE
⟹Area=16×8=128 cm2
Also, Area = AD × CF
⇒ 128 = AD × 10
⇒ AD = 12.8 cm
In the second parallelogram, area = 128 cm2 and CF = 16 cm.
Area = b × h = AD × CF
⟹128=AD×16
⇒ AD = 8 cm
But, AD = BC = 8 cm.
In the third parallelogram, DC = 12 cm, AD = 8 cm and AE = 6 cm.
Area = b × h = DC × AE
Area = 12 × 6 = 72 cm2
Also, Area = AD × CF
⇒ 72 = 8 × CF
⇒ CF = 9 cm