cylinder, but the base of the cone is larger than the base of the cylinder. So, a part of the base of the cone (a ring) is to be painted. So, the area to be painted orange = CSA of the cone + base area of the cone – base area of the cylinder = rl + r – r = [( . × .
× . cm = . cm Now, the area to be painted yellow = CSA of the cylinder + area of one base of the cylinder = r h + ( r ) = r ( h + r ) = ( . × .
cm Fig. . Example : Mayank made a bird-bath for his garden in the shape of a cylinder with a hemispherical depression at one end (see Fig. .
). The height of the cylinder is . m and its radius is cm. Find the total surface area of the bird-bath.
(Take = Solution : Let h be height of the cylinder, and r the common radius of the cylinder and hemisphere. Then, the total surface area of the bird-bath = CSA of cylinder + CSA of hemisphere = rh + r = r ( h + r ) ( ) cm = 33000 cm = . m EXERCISE . Unless stated otherwise, take = .
cubes each of volume cm are joined end to end. Find the surface area of the resulting cuboid. . A vessel is in the form of a hollow hemisphere mounted by a hollow cylinder.
The diameter of the hemisphere is cm and the total height of the vessel is cm. Find the inner surface