The students of Vidyalaya were asked to participate in a competition for making and decorating penholders in the shape of a cylinder with a base, using cardboard. Each penholder was to be of radius 3 cm and height 10.5 cm. The Vidyalaya was to supply the competitors with cardboard. If there were 35 competitors, how much cardboard was required to be bought for the competition? (Assume π =22/7)
Radius of the circular end of cylindrical penholder, r = 3 cm
Height of penholder, h = 10.5 cm
Surface area of a penholder = CSA of pen holder + Area of base of penholder
= 2πrh + πr2
= 2 × (22/7) × 3 × 10.5 + (22/7) ×32
= 1584/7
Therefore, Area of cardboard sheet used by one competitor is 1584/7 cm2
Area of cardboard sheet used by 35 competitors = 35 × 1584/7 = 7920 cm2
Therefore, 7920 cm2 cardboard sheet will be needed for the competition.