Question

the students of the vidhyalaya 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 3cm and height 10.5cm.the vidhyalaya was to supply the competitors with cardboard.if there were 35 competitors,how much cardboard was required to be bought for the competition.

Answer 1

The pen holder is in the shape of a cylinder.
CYLINDER:-
r= 3 cm
h=10.5cm
cardboard needed would be the LSA of cylinder + Are of the base circle.
=2πrh+πr²
=πr(2h+r)
= 22/7*3(2(10.5)+3)
=22/7*3(21+3)
=22/7*3(24)
=22*3*24/7
=1584/7cm²
=226.3(approx) cm²
so for one person the cardboard required would be 226.3 cm²
for 35 persons the cardboard required would be 1584/7*35
=1584*5
=7920 cm²
∴ the vidhyalaya has to buy 7920 cm² of cardboard.