Question

A building has a rectangular base. the length of the base measures 60 ft less than twice the width. The perimeter of this base is 810 ft. What are the dimensions of the base?

Answer 1

Check the picture below.

$\bf \textit{perimeter of a rectangle}\\\\ P=2(L+w)~~ \begin{cases} L=length\\ w=width\\[-0.5em] \hrulefill\\ P=810\\ L=2w-60\\ \end{cases}\implies 810 = 2[(2w-60)+w] \\\\\\ \cfrac{810}{2}=2w-60+w\implies 405=3w-60\implies 345=3w\implies \cfrac{345}{3}=w \\\\\\ \boxed{115=w}~\hfill 2(115)-60\implies 230-60\implies \boxed{170=L}$