Question

The perimeter of square and circumference of circle are equal,the area of square is 121$m^2$ then the area of circle is-

• A. $7\pi m^2$
• B. $14\pi m^2$
• C. $21\pi m^2$
• D. $49\pi m^2$

Answer 1

The correct option is D $49\pi m^2$

Perimeter of square $=$Circumference of circle
$\Rightarrow 4a=2\pi r$
$\Rightarrow r=\frac{4a}{2\pi }$
Given : $a^2=121$
$\Rightarrow a=11m$
$\therefore r=\frac{4\times 11\times 7}{2\times 22}$
$\Rightarrow r=7m$
Area of circle $=\pi r^2=49\pi m^2$
Hence D is the right answer