## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$r=\dfrac{A}{2\pi h}$
$\bf{\text{Solution Outline:}}$ To solve the given equation, $A=2\pi rh,$ for $r ,$ use properties of equality to isolate the variable. $\bf{\text{Solution Details:}}$ Using the properties of equality to isolate the variable, the equation above is equivalent to \begin{array}{l}\require{cancel} A=2\pi rh \\\\ \dfrac{A}{2\pi h}=\dfrac{2\pi rh}{2\pi h} \\\\ \dfrac{A}{2\pi h}=r \\\\ r=\dfrac{A}{2\pi h} .\end{array}