SOLUTION: The radii of two circles are 3 cm and 9 cm. Find the ratio of their circumferences

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Question 198551: The radii of two circles are 3 cm and 9 cm. Find the ratio of their circumferences
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!


Just by seeing the radii given, we can see the Ratio of the Circumference of the two Circles, C%5B1%5D%2FC%5B2%5D=3cm%2F9cm=1%2F3.

To show,
C%5B1%5D=2%28pi%29r=2%28pi%29%283%29=6pi%28cm%29

C%5B2%5D=2%28pi%29r=2%28pi%29%289%29=18pi%28cm%29


C%5B1%5D%2FC%5B2%5D=6pi%2F18pi=6cross%28pi%29%2F18cross%28pi%29=6%2F18=1%2F3

Thank you,
Jojo