The area of the curved surface of a cone of radius 2r and slant height , is

Find the length of cloth used in making a conical pandal of height 100 m and base radius 240 m, if the cloth is 100π m wide.

The number of surfaces of a cone has, is

The total surface area of a cone of radius and length 2l, is

A solid cylinder is melted and cast into a cone of same radius. The heights of the cone and cylinder are in the ratio