If two solid hemispheres of same base radius r units are joined together along their bases, then curved surface area of this new solid is

The height of a right circular cone whose radius is 5 cm and slant height is 13 cm will be

If the radius of the base of a right circular cylinder is halved keeping the same height, then the ratio of the volume of the cylinder thus obtained to the volume of original cylinder is

The total surface area of a cylinder whose radius is 

In a hollow cylinder, the sum of the external and internal radii is 14 cm and the width is 4 cm. If its height is 20 cm, the volume of the material in it is

If the radius of the base of a cone is tripled and the height is doubled then the volume is

The total surface area of a hemi-sphere is how much times the square of its radius.

A solid sphere of radius x cm is melted and cast into a shape of a solid cone of same radius. The height of the cone is

A frustum of a right circular cone is of height 16cm with radii of its ends as 8cm and 20cm. Then, the volume of the frustum is

A shuttle cock used for playing badminton has the shape of the combination of

A spherical ball of radius r₁ units is melted to make 8 new identical balls each of radius r₂ units. Then r_{1 :} r₂ is

The volume ( $cm^3$ ) of the greatest sphere that can be cut off from a cylindrical log of wood of base radius 1 cm and height 5 cm is

The height and radius of the cone of which the frustum is a part are h₁ units and r₁ units respectively. Height of the frustum is h₂ units and radius of the smaller base is r₂ units. If h₂ : h₁ = 1 : 2 then r₂ : r₁ is

The ratio of the volumes of a cylinder, a cone and a sphere, if each has the same diameter and same height is