Question

Question 11
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? $[Assume\pi =\frac{22}{7}]$

Answer 1

Radius (r) of the circular end of cylindrical penholder = 3 cm
Height (h) of the penholder = 10.5 cm
Surface area of 1 penholder = CSA of penholder + Area of base of penholder
$=2\pi rh+\pi r^2=[2\times \frac{22}{7}\times 3\times 10.5+\frac{22}{7}\times (3{)}^2]c{m}^2=(132\times 1.5+\frac{198}{7})c{m}^2=(198+\frac{198}{7})c{m}^2=\frac{1584}{7}c{m}^2$
Area of cardboard sheet used by 1 competitor $=\frac{1584}{7}c{m}^2$
Area of cardboard sheet used by 35 competitors
$=(\frac{1584}{7}\times 35)c{m}^2=7920c{m}^2$