Volume of the sphere V = 4/3*π*r^3
dV/dt = 4/3*π*3*r^2*dr/dt.
Substitute the values to get the result.
So I'm having trouble starting this problem.
A spherical snowball is melting in such a way that its radius is decreasing at the rate of 0.4 cm/min. At what rate is the volume of the snowball decreasing when the radius is 8 cm?