The circumferences of two circles are in the ratio `2:3`. What is the ratio between their areas?

Answer

`4:9`

Explanation

`(2piR_(1))/(2piR_(2))=2/3implies(R_(1))/(R_(2))=2/3`
`:.(piR_(1)^(2))/(piR_(2)^(2))=(R_(1)^(2))/(R_(2)^(2))=((R_(1))/(R_(2)))^(2)=(2/3)^(2)=4/9`
Required ratio `=4:9`