# 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 m².

**Solution:**

Given: The diameter of the cylindrical pillar is 50 cm and its height is 3.5 m and the rate of painting is ₹12.50 per m^{²}

The curved surface area of a right circular cylinder of base radius r and height h is 2πrh.

Height(h) of the pillar = 3.5 m

Radius(r) = diameter/2 = 50/2 cm = 25 cm = 0.25 m

Now, curved surface area of the pillar = 2πrh

= 2 × 22/7 × 0.25 m × 3.5 m

= 5.5 m²

We can calculate the cost of painting by multiplying the curved surface area of the pillar and the rate of painting per meter square.

Cost of painting the curved surface area at ₹12.50 per m^{²} = 12.50 × 5.5

= ₹ 68.75

Thus, cost of painting the curved surface of the pillar is ₹ 68.75.

**Video Solution:**

## 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 m².

### Class 9 Maths NCERT Solutions - Chapter 13 Exercise 13.2 Question 5:

**Summary:**

It is given that there is a cylindrical pillar which is 50 cm in diameter and 3.5 m in height. We have found that the cost of painting the curved surface of the pillar is ₹ 68.75.