The volume of a cylinder is v = 1/3 πr2h. if the radius is doubled and the height is halved, what will be the ratio of the new volume to the old volume

V(o) = 1/3 πr²h - old volume
V(n) = 1/3 π(2r)²(h/2)=1/3 π(2r)²(h/2)=1/3*4/2* πr²h=1/3*2* πr²h
V(n)/V(o)=1/3*2* πr²h/1/3 πr²h=2/1
V(n)/V(o)=2/1 - ratio
the volume will be doubled

The first digit is in the middle school 100s place