The surface area of a cylinder is increasing at a rate of $9\pi$ square meters per hour. The height of the cylinder is fixed at $3$ meters. At a certain instant, the surface area is $36\pi$ square meters. **What is the rate of change of the volume of the cylinder at that instant (in cubic meters per hour)?** [[☃ radio 1]] *The surface area of a cylinder with base radius $r$ and height $h$ is $2\pi r^2+2\pi r h$.* *The volume of a cylinder with base radius $r$ and height $h$ is $\pi r^2h$.*