Question

The width of a rectangle is 15 cm less than the length. the perimeter is 78 cm. find the rectangle's dimensions

Answer 1

Length (L): L

width (w): L - 15

Perimeter (P) = 2L + 2w

                78 = 2(L) + 2(L - 15)

                78 = 2L + 2L - 30

                78 = 4L - 30

               108 = 4L

                27 = L

width (w): L - 15   = 27 - 15   = 12

Answer: width = 12 cm, length = 27 cm