## Precalculus (6th Edition)

$h=\dfrac{S-2lw}{2(w+l)}$
$S=2lw+2wh+2hl$ $,$ for $h$ Take all terms without $h$ to the left side: $S-2lw=2wh+2hl$ Take out common factor $h$ from the right side: $S-2lw=h(2w+2l)$ Take $2w+2l$ to divide the left side: $\dfrac{S-2lw}{2w+2l}=h$ Rearrange: $h=\dfrac{S-2lw}{2w+2l}$ Take out common factor $2$ from the denominator to show a better looking answer: $h=\dfrac{S-2lw}{2(w+l)}$