## Elementary Algebra

The formula for the volume of a right circular cone is: V = $\frac{1}{3}$ $\times$ $\pi$ $\times$ $r^{2}$ $\times$ h Substitute 324$\pi$ for V and 9 for r to obtain: 324$\pi$ = $\frac{1}{3}$ $\times$ $\pi$ $\times$ $9^{2}$ $\times$ h 324$\pi$ = $\frac{1}{3}$ $\times$ $\pi$ $\times$ 81 $\times$ h Multiply both sides by 3 972$\pi$ = $\pi$ $\times$ 81 $\times$ h Divide both sides by 81$\pi$ h = 12