Question

The students of Byjus 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 Byjus 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

Radius of the circular end of cylindrical penholder, r = 3cm
Height of penholder, h = 10.5cm
Surface area of a penholder = CSA of pen holder + Area of base of penholder
$=2\pi rh+\pi r^2=(2\times \frac{22}{7}\times 3\times 10.5)+(\frac{22}{7}\times 3^2)=\frac{1584}{7}$
Therefore, Area of cardboard sheet used by one competitor is $\frac{1584}{7}c{m}^2$
So, Area of cardboard sheet used by 35 competitors = $35\times \frac{1584}{7}=7920c{m}^2$
Therefore, 7920 cm² cardboard sheet will be needed for the competition.