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)
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The radius of the circular end of the cylindrical penholder, r = 3cm
Height of penholder, h = 10.5cm
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, the Area of cardboard sheet used by one competitor is 1584/7 cm2
So, the Area of cardboard sheet used by 35 competitors = 35×1584/7 = 7920 cm2
Therefore, a 7920 cm2 cardboard sheet will be needed for the competition.