Question

In a building there are $24$ cylindrical pillars. The radius of each pillar is $28cm$ and height is $4cm$. Find the total cost of painting the curved surface area of all pillars at the rate of $Rs.8per{m}^2$.

Answer 1

C.S.A. of cylindrical $=2\pi rh$

$\Rightarrow$ C.S.A. of are pillar $=2\times \frac{22}{7}\times 28\times 4=704c{m}^2$

$\Rightarrow$ C.S.A. of 24 pillars $=24\times 704=16896c{m}^2$

$=16896\times {10}^{-4}{m}^2$

$=1.69m^2$

$\Rightarrow$ Total cost Rs. $8\times 1.69=Rs.13.52$