He perimeter of a rectangle is 126 centimeters. What are the dimensions of the sides if the width is seven centimeters shorter than the length?

1 Answer
Oct 12, 2016

The width of the rectangle is #28# cm, and the length is #35# cm.

Explanation:

The perimeter of a rectangle is given by the formula:
#P = 2(l + w)#,
where #l# is the length and #w# is the width of the rectangle.

In this problem, the width is explained in terms of the length, so that is how we will express each measurement. We will let
length = #l#
width = #l - 7#

Substituting our expressions for the length & width and #126# for #P#, we can solve the problem.

#126 = 2(l + l - 7)#
#126 = 2(2l - 7)#
#126 = 4l - 14#
#126 + 14 = 4l - 14 + 14#
#140 = 4l#
#140/4 = (4l)/4#
#35 = l#

This tells us that the length of the rectangle is #35# cm. To find the width, we substitute this value in our width expression.

width = #35 - 7 = 28#

So, the width of the rectangle is #28# cm.