Question

Find the ratio of the circumference of two circles whose radii are in the ratio 4:5

Answer 1

Let radius of first circle be r1
and the radius of second circle be r2


Given :-

$\frac{r1}{r2} = \frac{4}{5}$

Formula of circumference :- 2πr

$\frac{circum. \: of \: first \: circle}{circum. \: of \: second \: circle} = \frac{2\pi \: r1}{2\pi \: r2}$


$\frac{circum.of \: first \: circle}{circum.of \: second \: circle} = \frac{r1}{r2}$


So the ratio of their circumference
is also 4:5