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 12.50 per m.​

Answer 1

The cost of painting the curved surface of pillar is: 68.69

Explanation:

Given that

Diameter of pillar = d = 50 cm

As the height is in meters and we have to find the cost in per square meter, we have to convert cm into meters.

So,

d = 50/100 = 0.50 m

Now the radius will be:

`r = (d)/(2) = (0.50)/(2) = 0.25m`

Also

Height = 3.5m

The curved surface area of cylinder is given by:

`CSA = 2\pi rh`

Putting the values

`CSA = 2 * 3.14 * 0.25 * 3.5 = 5.495\ m^2`

It is given that the cost per square meter is 12.50

The total cost for 5.495 m^2 will be: 12.50 * 5.495 = 68.6875

Rounding off to nearest hundredth: 68.69

Hence,

The cost of painting the curved surface of pillar is: 68.69