Question

A copper wire when bent in the form of a square encloses an area of 121 cm . If the same wire is bent to form a circle , find the area of circle.

Answer 1

121= a square
a= 11 cm
2×22/7×r = 11×4
r/7= 1
r= 7 cm
area = 22/7×7×7
= 22×7
= 154 cm square

Answer 2

Answer:

Answer:

Solution:

Let "α" be the side of the square

Given:

Area of the square = 121 sq.cm.

α² = 121

Since 11² = 121

α = 11 cm

Perimeter of the square = 4a units

Which means,

$= 4 \times 11 cm$

$= 44 \: \: \: cm$

Length of the copper wire = Perimeter of the square

That is, Length of the copper wire = 44 cm

The copper wire is bent in the form of a circle

So,

The circumference of the circle = Length of the copper wire

Therefore, circumference of the circle = 44 cm

$2\pi r = 44 \:$

$2 \times \frac{22}{7} \times r \: = 44$

By simplifying we get,

$r = \frac{44 \times 7}{44}$

$r = 7cm$

Therefore ,

Area of the circle = π r²

$= \frac{22}{7} \times 7cm \times 7cm$

And therefore, Area of the circle is 154 cm².