Cylinder Volume Varies

Question

The volume of a cylinder varies directly with its height and the square of its radius. How does the volume change if the radius is doubled and the height is tripled?

Answer 1

Volume = pi* r^2*h

 

Radius ---- doubled.  r is 2r

 

Height = 3h

 

New volume =pi*(2r)^2*3h

 

                 = 12*pi*r^2*h

 

So, the new volume is 12 times the old one.