## Precalculus (6th Edition) Blitzer

$h=\frac{A-2lw}{2l+2w}$ Formula gives surface area (A) of a rectangular prism
$A = 2lw + 2lh + 2wh$ $A-2lw=2lh + 2wh$ $A-2lw=h(2l+2w)$ $h=\frac{A-2lw}{2l+2w}$