Question

The students of a Vidyalaya were asked to participate in a competition for making and decorating pen holders in the shape of a cylinder with a base, using cardboard. Each pen holder 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 carboard was required to be bought for the competition?

Answer 1

We have, $r=3$cm, $h=10.5$cm
$\therefore$ Area of cardboard$=35\times \{2\pi rh+\pi r^2\}c{m}^2$
$=35\times \pi r(2h+r)c{m}^2=35\times \frac{22}{7}\times 3\times 24c{m}^2=7920c{m}^2$.