Question

Question 5
A cylindrical pillar is 50 cm in diameter and 3.5 m in height. Find the cost of painting the curved surface of the pillar at the rate of Rs. 12.50 per $m^2.[Assume\pi =\frac{22}{7}]$

Answer 1

Height (h) of the cylindrical pillar = 3.5 m
Radius (r) of the circular end of the pillar $\frac{50}{2}=25cm$
CSA of pillar $=2\pi rh$
$=(2\times \frac{22}{7}\times 0.25\times 3.5)m^2=(44\times 0.125)m^2=5.5m^2$
Cost to paint $1m^2$ area = Rs. 12.50
Cost to paint $5.5m^{2}area=Rs.(5.5\times 12.50)$
= Rs. 68.75
Therefore, the cost of painting the CSA of the pillar is Rs. 68.75.