Question

The areas of two circles are in the ratio 4 : 9. What is the ratio between their circumferences ?

Answer 1

Let the radius of one circle be r and radius of other circle be R

Then we have

πr^2/πR^2=4/9

r^2/R^2=4/9

r/R=2/3

now ratio of circumference of two circles is given by

2πr/2πR=r/R=2/3

2:3 is the ratio between their circumferences