Question

The radii of two circles are in the ratio $2:3$. The ratio of their areas is
$\left(a\right)$ $2:3$

$\left(b\right)$ $4:9$

$\left(c\right)$ $3:2$

$\left(d\right)$ $9:4$

Answer 1

Let $r_1$ and $r_2$ be the radius of the two circles.

$\Rightarrow$ $r_1$$:$$r_2$$=$$2:3$
Now,
Ratio of areas $=\pi r_1^2:\pi r_1^2$

$=r_1^2:r_1^2$

$=2^2:3^2$

$=4:9$

Thus, the required ratio is $4:9$.
Hence, the correct option is $\left(b\right)$ .