The numerical value of the volume of a sphere is twice the numerical value of its surface area. Find the radius of the sphere.

Two solid spheres with radii of 1 cm and 6 cm lengths are melted and a hollow sphere with an outer radius of 9 cm is made. Determine the inner radius of the new hollow sphere.

If the ratio of the volumes of two solid spheres is 27 : 8, then the ratio of their curved surface area is (a) 1 : 2 (b) 9 : 4 (c) 1 : 8 (d) 1 : 16

Melting a solid Lead sphere of diameter 12 cm, three small solid spheres are made. If the ratio of the diameter of the small spheres is 3 : 4 : 5 then find the radius of each small sphere

How much percent of the curved surface area of a sphere will be increased if the radius is doubled?

Calculate how many spherical marbles with 1 cm radius each may be formed by melting a solid sphere of iron having 8 cm of radius.

If the length of the radius of a sphere is increased by 50%, find how much percent will be increased of its curved surface area.

The greatest volume of a solid cone which can be cut off from a solid hemisphere of radius r unit is ______.

State True or False: The ratio of whole surfaces of a solid sphere and a solid hemisphere of equal radius is 2 : 1.

What is the name of the solid which is composed of only one surface?

If radius of a sphere is r and volume v, then v ∝ ___.

The volume of a solid sphere having radius 2r units is: (a) r³ cm³ (b) r³ cm³ (c) r³ cm³ (d) r³ cm³