## Algebra: A Combined Approach (4th Edition)

$h=\dfrac{S-2\pi r^{2}}{2\pi r}$
$S=2\pi rh+2\pi r^{2}$, for $h$ Substract $2\pi r^{2}$ to both sides of the equation: $2\pi rh+2\pi r^{2}-2\pi r^{2}=S-2\pi r^{2}$ $2\pi rh=S-2\pi r^{2}$ Divide both sides of the equation by $2\pi r$: $\dfrac{2\pi rh}{2\pi r}=\dfrac{S-2\pi r^{2}}{2\pi r}$ $h=\dfrac{S-2\pi r^{2}}{2\pi r}$