# Diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. Find its curved surface area.

**Solution:**

Diameter of the base of the cone is 10.5 cm and slant height is 10 cm.

Curved surface area of a right circular cone of base radius, 'r' and slant height, 'l' is πrl.

Diameter, d = 10.5cm

Radius, r = 10.5/2 cm = 5.25 cm

Slant height, l = 10 cm

Curved surface area = πrl

= 22/7 × 5.25 × 10

= 165 cm²

Thus, curved surface area of the cone = 165 cm².

**Video Solution:**

## Diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. Find its curved surface area.

### Class 9 Maths NCERT Solutions - Chapter 13 Exercise 13.3 Question 1:

**Summary:**

It is given that the diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. We have found that the Curved surface area of the cone is 165 cm².