A sector with radius ‘r’ and length of its arc ‘l’ is cut from a circular sheet of paper. Fold it as a cone. How can you derive the formula of its curved surface area A =`pi rl `

A sector with radius r and length of its are I is cut from a circular sheet of paper. Fold it as a cone. How can you derive the formula of its curved Surface area A = pi r l

The slant height of a right circular cone is 10 m and its height is 8 m. Find the area of its curved surface?

A rectangular piece of length 12 cm and breadth 4 cm is folded to form a cylinder. Find its curved surface area.

Prove that the radius of the right circular cylinder of greatest curved surface area which can be inscribed in a given cone is half of that of the cone.

A cone is made from a circular sheet of radius sqrt(3) by cutting out a sector and giving the cut edges of the remaining piece together .The maximum volume attainable for the cone is

From a circle of radius 15cm . A sector with angle 216 ^(@) is cut out and its bounding radius are bent so as to form a cone . Find its volume.

A toy is made in the form of hemisphere surmounted by a right cone whose circular base is joined with the plane surface of the hemisphere. The radius of the base of the cone is 7 cm. and its volume is 3/2 of the hemisphere. Calculate the height of the cone and the surface area of the toy correct to 2 places of decimal. ("Take "pi=3""1/7)