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

The number of surfaces of a cone has, is

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

The slant height of a cone is increased by 10%. If the radius remains the same, the curved surface area is increases by