Question

The ratio of the diameters of two circles is 2:3. What is the ratio of their circumferences?
(2 marks)

Answer 1

Circumference of a circle = $\pi d$
where d is the diameter of the circle
(1 mark)
Let $d_1$ and $d_2$ be the diameters of two circles respectively.

$\frac{d_1}{d_2}=2:3$ (Given)

Now, the ratio of their circumferences
= $\frac{\pi d_1}{\pi d_2}=\frac{d_1}{d_2}=2:3$