Question

The width of a rectangle is 1/2 its length. The perimeter of the rectangle is 540 ft. What is the length, in feet, of the rectangle? 

Answer 1

The rectangle

The equation of the perimeter of a rectangle is

$P=2l+2w$

We know the value of the perimeter and have a unknow for l(lenght) and w(width) so, we can replace and we will have an equation with the variable x(length)

replacing

$540=2(x)+2(\frac{x}{2})$

simplify parenthesis

$540=2x+x$

add x's

$\begin{gathered} 540=3x \\ \end{gathered}$

and solve for x dividing the equation on 3

$x=180$

the value of x or the length is 180 ft