Question

The length of a rectangle is 5 m greater than the width. The perimeter is 150 m. find the width

Answer 1

P = perimeter

Perimeter of a rectangle = l + l + w + w

or  P = 2l + 2w

You know:

P = 150 m

l = w + 5     [length is 5 m greater than the width]

P = 2l + 2w        Plug in what you know

150 = 2(w + 5) + 2w     Simplify, distribute/multiply 2 into (w + 5)

150 = 2w + 10 + 2w

150 = 4w + 10     Subtract 10 to both sides of the equation

140 = 4w       Divide 4 on both sides

35 = w

PROOF               l = w + 5 --->  l = 40

P = 2l + 2w

150 = 2(40) + 2(35)

150 = 80 + 70

150 = 150