Calculus
posted by jaden .
The volume of a cone of radius r and height h is given by V=1/3pir^2h. If the radius and the height both increase at a constant rate of 1/2 centimeter per second, at what rate, in cubic centimeters per second, is the volume increasing when the height is 9 centimeter and the radius is 6 centimeters?
explain please

annnnd....
a)1/2pi
b) 10pi
c) 24pi
d) 54pi
e) 108pi