The material of a cone is converted into the shape of a cylinder of equal radius.  If the height of the cylinder is 5 cm, the height of cone is

The surface area of a sphere whose radius is 2.1 metres. 

A toy in the shape of a square pyramid has base edge 25 centimeters and slant height 8 centimeters. Then its lateral surface area is

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

The height of a cylinder tower is 14 cm and its curved surface area is 264 cm².  The radius of its base is

The ratio of total surface area to lateral surface area of a cylinder whose radius is 80 cm and height is 20 cm is

A vessel is in the form of an inverted cone. Its height is 11 cm and the radius of its top which is open is 2 . 5 cm.  It is filled with water up to the rim.  When lead shots, each of which is a sphere of radius 0.25 cm are dropped in to the vessel, ²/₅ of the water flows out.  Find the number of lead shots dropped in to the vessel

A cylindrical tower is 5 m in diameter and 14 m high.  The cost of white washing its curved surface at 50 paisa per m² is

The volume of a sphere is ⁸⁸/₂₁ ( 14 )³ cm ³.  The curved surface of this sphere is

If the radii  of two spheres are in ratio  1: 2. then ratio of their surface areas will  be