Question

A rectangular is 4 times as long as it is wide . if the area is 16 square feet, find its perimeter

Answer 1

if say we have a widht of w, and its length is 4 times as long as w, then its length is 4*w or 4w.

$\bf \textit{area of a rectangle}\\\\ A=Lw~~ \begin{cases} L=4w\\ A=16 \end{cases}\implies 16=(4w)w\implies 16=4w^2 \\\\\\ \cfrac{16}{4}=w^2\implies 4=w^2\implies \sqrt{4}=w\implies \boxed{2=w} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill \stackrel{perimeter}{\stackrel{L}{4(2)}+\stackrel{w}{2}\implies 10}\hfill$