# The length of a rectangle is 3 times the width. The perimeter is 65.6 cm. How do you find the width?

Nov 23, 2016

Width is $8.2$ centimeters, length is $24.6$ centimeters.

#### Explanation:

Let $l = \text{length}$, and $w = \text{width}$

The two equations are:
$l = 3 w$
$2 l + 2 w = 65.6$

Use substitution - substitute $l = 3 w$ into the second equation to find w:
$2 \left(3 w\right) + 2 w = 65.6$
$6 w + 2 w = 65.6$
$8 w = 65.6$
$w = 8.2$

Use substitution again - substitute $w = 8.2$ into the first equation to find l:
$l = 3 \left(8.2\right)$
$l = 24.6$