# A hemispherical bowl is made of steel, 0.25 cm thick. The inner radius of the bowl is 5 cm. Find the outer curved surface area of the bowl.

**Solution:**

Given: Inner radius of the bowl is 5 cm and the thickness of the steel is 0.25cm.

Since the hemispherical bowl is made up of 0.25cm thick steel, we can find the outer radius of the bowl by adding thickness to the inner radius.

The curved surface area of a hemisphere of radius r = 2πr^{2}

The inner radius of the bowl, r = 5cm

Thickness of steel = 0.25cm

Outer radius of the bowl, R = 5cm + 0.25cm = 5.25cm

Outer CSA of the hemisphere = 2πR^{2}

= 2 × 22/7 × 5.25cm × 5.25cm

= 173.25 cm^{2}

Thus, the outer curved surface area of the hemisphere is 173.25 cm^{2}.

**Video Solution:**

## A hemispherical bowl is made of steel, 0.25 cm thick. The inner radius of the bowl is 5 cm. Find the outer curved surface area of the bowl.

### Class 9 Maths NCERT Solutions - Chapter 13 Exercise 13.4 Question 8:

**Summary:**

It is given that there is a hemispherical bowl with an inner radius of 5 cm is made up of 0.25 cm thick steel. We have found that the outer curved surface area of the hemispherical bowl is 173.25 cm^{2}.