Question

ratio of radii of a circle is 2:3. find the ratio of their circumference

Answer 1

Ratio of circle = 2:3
Radius of first circle = 2x
Radius of second circle = 3x
Ratio of circumference will be,
2pie2x:2pie3x
= 2:3

Hence the ratio of the circumference will be 2:3.

hope this helps you....
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Answer 2

R1:R2=2:3
C1:C2= 2pie. R1: 2 pie R2
C1:C2=2:3