Question

In a building, there are $24$ cylindrical pillars. For each pillar, the radius is $28m$ and the height is $4m.$ Find the total cost of painting the curved surface area of the pillars at the rate of $Rs.8$ per metre square

Answer 1

Radius of cylinderical pillars, $r=28cm=0.28m$ [$\because 1m=100cm$]

Height, $h=4m$

The curved surface area of a cylinder $=2\pi rh$

The curved surface area of a cylindrical pillar $=2\times \frac{22}{7}\times 0.28\times 4=7.04m^2$

The curved surface area of 24 such pillars $=7.04\times 24=168.96m^2$

The cost of Painting an area of $1m^2=Rs.8$

So, the total cost of painting an area of $168.96m^2=168.96\times 8=Rs.1,351.68$