## Elementary Algebra

Since the width is stated in terms of the length, we can let l represent the length. Since the width is one-half its length, and the length is l, the the width is $\frac{1}{2}l$. The formula for the perimeter of the rectangle is width + width + length + length The perimeter of the rectangle is 54, so we set up the following equation: l + l + $\frac{1}{2}$l + $\frac{1}{2}$l = 54 3l = 54 Divide both sides by 3. l = 18 Since the length is 18, the width is $\frac{1}{2}$l = $\frac{1}{2}$ $\times$ 18 = 9.