Chapter 3 - Equations and Problem Solving - 3.1 - Solving First-Degree Equations - Problem Set 3.1 - Page 100: 84

$h=\dfrac{3V}{\pi r^2}$

Using the properties of equality, the given equation, $ V=\dfrac{1}{3}\pi r^2h ,$ is equivalent to \begin{array}{l}\require{cancel} 3V=\pi r^2h \\\\ \dfrac{3V}{\pi r^2}=\dfrac{\pi r^2h}{\pi r^2} \\\\ h=\dfrac{3V}{\pi r^2} .\end{array}