## anonymous 5 years ago The radius of a sphere is increasing at a constant rate of 2cm/sec. At the instant when the volume of the sphere is 36π cm^3, what is the rate that the surface area is increasing? Surface area=4π r^2 Volume=4/3π r^3

1. anonymous

$S(r(t))=4\pi r^2$ $S'(r(t))=8\pi r r'$ and you are told that $r'=2$ so this becomes $S'(r(t))=16\pi r$ now your only job is to find r and substitute

2. anonymous

How do I find r?