Question

The ratio of the radii of two circles is 3 : 2. What is the ratio of their circumference?

• A. 2:3
• B. 1:3
• C. 3:2
• D. 3:1

Answer 1

The correct option is

C

3:2

Circumference of a circle = $2\pi r$
Where $r$ is the radius of the circle

Let $r_1$ and $r_2$ are radii of two circles respectively.

$\frac{r_1}{r_2}=3:2$ (Given)

Now, the ratio of their circumference
= $\frac{2\pi r_1}{2\pi r_2}=\frac{r_1}{r_2}=3:2$