Solution:
Let the radius of the base of a right circular cylinder be r and height be h.
Volume of the cylinder, V1 = r2h
The radius of the base of a right circular cylinder is halved and the height is doubled.
So radius of new cylinder = r/2
Height of new cylinder = 2h
Volume of the new cylinder, V2 = r2h
= (r/2)2 ×2h
= ½ r2h
So ratio of volume of new cylinder to the original cylinder , V2/V1= ½ r2h/r2h = ½
Hence the required ratio is 1:2.