Grade 10 Math Help! Assessment Tomorrow!?

Question

A rectangle with a perimeter of 180cm is four times longer than it is wide. What are its dimensions?

Answer 1

Given that,

                   Perimeter of a rectangle = 180cm

                   Rectangle is 4 times longer than its width i.e, l=4b

Let us assume that,

                  Length of the rectangle be l

                  Width or breadth of the rectangle be b

                  Perimeter be P

Perimeter P = 2(l+b)     [Where perimeter of the rectangle is 2(length + breadth)]

             => 2l + 2b = 180

             => 2(4b) + 2b = 180       where l=4b

             => 8b +2b =180

             => 10b = 180

             => b = 180/10

             => b =18

Therefore width of the rectangle b =18.

Given that length l = 4b

                          => l = 4(18)

                          => l = 72

Therefore length of the rectangle l =72.

Therefore the dimensions of the rectangle are 72 and 18.