Question

If the circumference of two circle are in the ratio $3:4.$ Find the ratio of their areas.

Answer 1

Circumference of two circles $=3:4$

$\frac{{2\pi r}_1}{{2\pi r}_2}=\frac{3}{4}$

$\frac{r_1}{r_2}=\frac{3}{4}$

Ratio of radius $=3:4$

Area $=\frac{{\pi r}_1^2}{{\pi r}_2^2}=\frac{3^2}{4^2}=\frac{9}{16}$

Ratio of areas $=9:16$