The cones have the same volume and their base radii are in the ratio 4 : 5. What is the ratio of their heights?

A sector of central angle 216° is cut out from a circle of radius 25 centimetres and is rolled up into a cone. What are the base radius and height of the cone? What is its volume?

The base radii of two cones are in the ratio 3 : 5 and their heights are in the ratio 2 : 3. What is the ratio of their volumes?

The surface area of a solid sphere is 120 square centimetres. If it is cut into two halves, what would be the surface area of each hemisphere?

The volume of two spheres are in the ratio 27 : 64. What is the ratio of their radii? And the ratio of their surface areas?