The curved surface area of one cone is twice that of the other while the slant height of the latter is twice that of the former. The ratio of their radii is

If the radius of the base of a right circular cone is 3r and its height is equal to the radius of the base, then its volume is

If the volume of two cones are in the ratio 1 : 4 and their diameters are in the ratio 4 : 5, then the ratio of their heights, is

If the height and radius of a cone of volume V are doubled, then the volume of the cone is,

The ratio of the volume of a right circular cylinder and a right circular cone of the same base and height, is