According to figure in parallelogram ABCD, Ratio of base BC and height AE is 5 : 2.
Let base of parallelogram = 5x
Height of parallelogram = 2x
Area of parallelogram = 640
⇒ Base x Height = 640
⇒ 5x × 2x = 640
⇒ 10x2 = 640
⇒ x2 = 640/10
⇒ x2 = 64 ⇒x = 8
Base of parallelogram = 5x = 5 x 8 = 40 cm
Height of parallelogram = 2x = 2 × 8 = 16 cm