The number of surfaces of a cone has, is

Find the area of metal sheet required in making a closed hollow cone of base radius 7 cm and height 24 cm.

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

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