Question

Find the ratio of the circumferences of two concentric circles of radii $2m$ and $3m$.

Answer 1

Circumference of 1st circle=$2\ast \pi \ast r_1$

circumference of 2nd circle=$2\ast pi\ast r_2$

Ratio of their circumference of circles=r1:r2

$\therefore$ Ratio of circumference of given circle = $\frac{2}{3}$