3.8 Exercise 78

Determine the function described and then use it to answer the question.

The volume of a right circular cone, $V ,$ in terms of its radius, $r ,$ and its height, $h ,$ is given by $V = \frac{1}{3} \pi r^{2} h .$ Express $r$ in terms of $V$ if the height of the cone is 12 inches and find the radius of a cone with volume of 50 cubic inches.