Question

If the ratio of the areas of the two circles is 25 : 16, then the ratio of their circumferences is

• A. $\frac{625}{500}$
• B. $\frac{4}{5}$
• C. $\frac{5}{4}$
• D. $\frac{500}{625}$

Answer 1

Answer: (A), (C)

$\frac{625}{500}$
$\frac{5}{4}$

$\frac{\pi r_1^2}{\pi r_2^2}=\frac{25}{16}$
$\frac{r_1}{r_2}=\frac{5}{4}$
$\frac{2\pi r_1}{2\pi r_2}=\frac{5}{4}=\frac{5\times 125}{4\times 125}=\frac{625}{500}$