Two circular cylinders of equal volumes have their heights in the ratio 1 : 2. Find the ratio of their radii.

The ratio between the radius of the base and the height jof a cylinder is 2 : 3. Find the total surface area of the cylinder, if its volume is 1617 cm³.

The curved surface area of a cylindrical pillar is 264 m² and its volume is 924 m³. Find the diameter and the height of the pillar.

The height of a right circular cylinder is 10/5 m. Three times the sum of the areas of its two circular faces is twice the area of the curved surface. Find the volume of the cylinder.

How many cubic metres of earth must be dug-out to sink a well 21 m deep and 6 mdiameter?