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 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? (Take π = 3.14).
It is given that
Radius of the circular part of the penholder (r) = 3 cm
The height of the penholder (h) = 10.5 cm
Surface area of one penholder (S.A)
= Curved surface area of penholder + Area of the circular base of penholder
$=2 \pi r h+\pi r^{2}$
$=(2 * 3.14 * 3 * 10.5)+3.14 * 3^{2}$
= 198 + 198/7
$=1584 / 7 \mathrm{~cm}^{2}$
The total area of cardboard sheet used by one competitor $=1584 / 7 \mathrm{~cm}^{2}$
The total area of cardboard sheet used by 30 competitors $=1584 / 7 * 35 \mathrm{~cm}^{2}$
$=7920 \mathrm{~cm}^{2}$
Therefore, the school needs to buy $7920 \mathrm{~cm}^{2}$ 2 of cardboard sheet for the competition.