# A closed cylindrical tank of radius 7 m and height 3 m is made from a sheet of metal. How much sheet of metal is required?

**Solution:**

Let's construct a diagram according to the given question.

Height of the cylindrical tank (h) = 3 cm

Radius of the cylindrical (r) = 7 cm

Lateral surface area of the cylinder = 2πrh = 2 × 22/7 × 7 × 3 = 132 m² …(1)

Area of circlular base = Area of top = πr²

= 22/7 × 7 m × 7 m = 154 m² …(2)

The metal sheet required will be equal to the total surface area of the cylinder.

Total surface area of cylinder = Lateral surface area of the cylinder + Area of two circular end

= 2πrh + 2πr²

= 132 m² + 308 m² [substituting values from (1) and (2)]

= 440 m²

Thus, the amount of metal sheet required will be 440 m².

**Video Solution:**

## A closed cylindrical tank of radius 7 m and height 3 m is made from a sheet of metal. How much sheet of metal is required?

### Maths NCERT Solutions Class 8 - Chapter 11 Exercise 11.3 Question 7

**Summary:**

A closed cylindrical tank of radius 7 m and height 3 m is made from a sheet of metal. 440 m² sheet is required.