The length of the rectangle 5cm more than twice the width.The perimeter is 70.What is the area?

Answer 1

The length of the rectangle 5cm more than twice the width.

This mean :

L = 5 + 2 W

P = 2 W + 2 L = 2 ( W + L )

70 = 2 ( W + L )

70 = 2 ( W + 5 + 2W )

70 = 2 ( 3 W + 5 ) Divide both sides by 2

70 / 2 = 2 ( 3 W + 5 ) / 2

35 = 3 W + 5 Subtract 5 to both sides

35 - 5 = 3 W + 5 - 5

30 = 3 W Diwide both sides by 3

30 / 3 = 3 W / 3

10 = W

W = 10 cm

L = 5 + 2 W = 5 + 2 * 10 = 5 + 20 = 25 cm

Proof :

P = 2 ( W + L ) = 2 ( 10 + 25 ) = 2 * 35 = 70 cm