Question 21

# A copper wire when bent in the form of a square encloses an area of $$121\ cm^2$$. If the same wire is bent into the form of a circle, find the area of the circle:(Use:$$\pi=\frac{22}{7}$$)

Solution

Given

Encloses area by forming the square = 121$$cm^2$$

we know that

Area of square =$$a^2$$

so,

$$a^2$$=121

a=11 cm

now perimeter of square = perimeter of circle according to question 

from here we get r=7 cm

Area of circle =$$\pi\text{r}^2$$

= $$\frac{22}{7}\cdot7^2=154cm^2$$ Ans