Question

If the circumference of two circle are in the ratio 3:1then the ratio of their areas will be

Answer 1

Given,C1:C2=3:1

2pieR1:2pieR2=3:1

So,R1:R2=3:1

Area1:Area2=pie(R1)^2:pie(R2)^2

                   =(R1/R2)^2

                  =(3/1)^2

                  =9:1

Alternatively You can learn that Ratio of Areas is square of Ratio of Circumferences.