If circumferences of two circles are in the ratio $3:1$ , what is the ratio of their areas?

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Answer 1 · 2017-05-19T05:20:32

The ratio of areas of two circles will be $9:1$

The formula for circumference $C$ of a circle is $2pir$

Hence $Cpropr$ , $2pi$ being constant

The formula for area $A$ of a circle is $pir^2$

Hence $Apropr^2$ , $pi$ being constant

Hence, as ratio of circumferences of two circles is $3:1$

ratio of areas of two circles will be $3^2:1^2$ or $9:1$

If circumferences of two circles are in the ratio 3:13:1, what is the ratio of their areas?