A metal cube of edge 12 cm is melted and formed into three smaller cubes. If the edges of two smaller cubes are 6 cm and 8 cm, the edge of the third smaller cube is?

The ratio of radii of two right circular cylinders (A and B) is 2:3. The ratio of volumes of the cylinders A and B is 9:7, then what is the ratio of the heights of the cylinders A and B?

A solid sphere of radius 15 cm is melted into a hollow cylinder of uniform thickness. If the external radius of the base of the cylinder is 9 cm and its height is 100 cm, find the uniform thickness of the cylinder.

64 small solid iron spheres of radius 'r' are melted to form a big sphere of radius R. If S and S' are surface areas of the small and the big sphere respectively, then find the ratio S' : S.

The volume of cylinder is

64 solid iron spheres of radius r are melted to form a sphere of radius R. Find R : r.

A hemisphere of radius 4 cm is cut from a solid sphere of radius 4 cm. What is the remaining volume of the sphere? (Use $\pi \approx 3.14$)