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Question
The students of a 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 "pi=22/7]`
Solution
Radius (r) of the circular end of cylindrical penholder = 3 cm
Height (h) of penholder = 10.5 cm
Surface area of 1 penholder = CSA of penholder + Area of base of penholder
= 2πrh + πr2
`=[2xx22/7xx3xx10.5+22/7xx(3)^2]cm^2`
`=(132xx1.5+198/7)cm^2`
`=(198+198/7)cm^2`
`=1584/7cm^2`
`"Area of cardboard sheet used by 1 competitor "=1584/7cm^2`
Area of cardboard sheet used by 35 competitors
`=(1584/7xx35)cm^2=7920cm^2`
Therefore, 7920 cm2 cardboard sheet will be bought.
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