A spherical snowball is melting in such a way that its diameter is decreasing at rate of 0.2 cm/min. At what rate is the volume of the snowball decreasing when the diameter is 9 cm.

Answer 1

"..diameter is decreasing at rate of 0.2 cm/min"
---> dd/dt = .2, so dr/dt = .1 cm/min

V= (4/3)π r^3
dV/dt = 3π r^2 dr/dt
insert your given data