# A right circular cylindrical tunnel of diameter 2 m and length 40 m is to be constructed from a sheet of iron. The area of the iron sheet required in m2, is - Mathematics

MCQ

A right circular cylindrical tunnel of diameter 2 m and length 40 m is to be constructed from a sheet of iron. The area of the iron sheet required in m2, is

#### Options

• 40 $\pi$

• 80 $\pi$

• 160 $\pi$

• 200 $\pi$

#### Solution

Let r be the radius of the cylinder and h be its height.

It is given that:

2r = 2 ⇒ r = 1 m

And,

h = 40 m

Therefore, total surface area S of the sheet required is:

S = 2 pirh

⇒ S = 2pi xx 1xx40

⇒ S = 80pi  m^2

Concept: Surface Area of Cylinder
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#### APPEARS IN

RD Sharma Mathematics for Class 9
Chapter 19 Surface Areas and Volume of a Circular Cylinder
Exercise 19.4 | Q 11 | Page 29

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