# A cylindrical pillar is 50 cm in diameter and 3.5 m in height.

Question:

A cylindrical pillar is $50 \mathrm{~cm}$ in diameter and $3.5 \mathrm{~m}$ in height. Find the cost of painting the curved surface of the pillar at the rate of Rs $12.50$ per $\mathrm{m}^{2}$. (Take $\pi=3.14$ )

Solution:

Given that

Height of cylindrical pillar = 3.5 m

Radius(r) of circular end of pillar = 50/2 = 25 cm = 0.25 m

Curved surface area of cylindrical pillar = 2π = 2 * 3.14 * 0.25 * 3.5

$=5.5 \mathrm{~m}^{2}$

The cost of whitewashing $1 \mathrm{~m}^{2}$ is Rs $12.50$

Cost of whitewashing $5.5 \mathrm{~m}^{2}$ area $=$ Rs $(12.5 * 5.5)=$ Rs $68.75$

Thus the cost of whitewashing the pillar is Rs 68.75