# Ex.11.3 Q11 Perimeter and Area - NCERT Maths Class 7

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## Question

A circle of radius $$2\rm\, cm$$ is cut out from a square piece of an aluminum sheet of side $$6\rm\, cm$$. What is the area of the left-over aluminum sheet? (Take $$π = 3.14$$)

Video Solution
Perimeter And Area
Ex 11.3 | Question 11

## Text Solution

What is known?

A square piece of an aluminum sheet of side $$6\rm\, cm$$ from which a circle of radius $$2\rm\, cm$$ is cut out.

What is unknown?

The area of the left-over aluminum sheet.

Reasoning:

First, find the area of the piece of the aluminum sheet then subtract the area of the circle from it and you can get the area of the left -over aluminum sheet.

Steps:

Side of square piece of aluminum sheet $$=$$ $$6\rm\, cm$$ and radius of circle $$=$$ $$2\rm\, cm$$

Area of aluminium sheet left $$=$$ Total area of square aluminum sheet $$-$$ Area of circle

\begin{align} &= {\rm{Side}} \times {\rm{Side}} - \pi {r^2}\\ &= 6 \times 6 - 3.14 \times 2 \times 2\\ &= 36 - 12.56\\ &= 23.44\;\rm c{m^2}\end{align}

Therefore, the area of aluminum sheet left is $$23.44 \rm\,cm^2.$$

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