Question

If circumference of a circle is $3\pi$, then its area is

• A. $\frac{7\pi }{2}$
• B. $9{\pi }^2$
• C. $4{\pi }^2$
• D. $\frac{9\pi }{4}$

Answer 1

The correct option is D $\frac{9\pi }{4}$

$\Rightarrow$ Circumference of a circle $=3\pi$

$\Rightarrow$ $2\pi r=3\pi$

$\Rightarrow$ $2r=3$

$\Rightarrow$ $r=\frac{3}{2}$

$\Rightarrow$ Area of a circle $=\pi r^2$

$=\pi \times {\left(\frac{3}{2}\right)}^2$

$=\frac{9}{4}\pi$