Answer:
![Rs. 1056](https://tex.z-dn.net/?f=Rs.%201056)
Step-by-step explanation:
Given: Diameter of each pillar= 1.4m
Height= 6m
Cost of painting the curved surfaces of all the pillars at the rate of Rs ![10\ per\ m^{2}](https://tex.z-dn.net/?f=10%5C%20per%5C%20m%5E%7B2%7D)
First lets find out radius of each pillar.
Radius (r)= ![\frac{Diameter}{2}](https://tex.z-dn.net/?f=%5Cfrac%7BDiameter%7D%7B2%7D)
∴ Radius (r)= ![\frac{1.4}{2} = 0.7\ m](https://tex.z-dn.net/?f=%5Cfrac%7B1.4%7D%7B2%7D%20%3D%200.7%5C%20m)
Now, finding area of cylindrical pillar.
Formula; Area of curved surface= ![2\pi rh](https://tex.z-dn.net/?f=2%5Cpi%20rh)
⇒ Area of curved surface= ![2\times \frac{22}{7} \times 0.7\times 6 = 26.4\ m](https://tex.z-dn.net/?f=2%5Ctimes%20%5Cfrac%7B22%7D%7B7%7D%20%5Ctimes%200.7%5Ctimes%206%20%3D%2026.4%5C%20m)
∵ There are four cylindrical pillars.
∴ Curved surface area of four pillar= ![4\times 26.4\ m= 105.6\ m^2](https://tex.z-dn.net/?f=4%5Ctimes%2026.4%5C%20m%3D%20105.6%5C%20m%5E2)
Curved surface area of four pillar is 105.6 m²
Next, finding the cost of painting the pillars.
As given, cost of painting is Rs 10 per m².
∴ Cost of painting 105.6 m²= ![10\times 105.6 m^{2} = Rs. 1056](https://tex.z-dn.net/?f=10%5Ctimes%20105.6%20m%5E%7B2%7D%20%3D%20Rs.%201056)
∴ The cost of painting the curved surfaces of all the pillars is Rs.1056.