A point O is situated on a circle of radius R. With centre O, another circle of radius 3R/2 is described. Inside the crescent shaped area intercepted between these circles, a circle of radius R/8 is placed. If the same circle moves in contact with the original circle of radius R, find the length of the arc described by its centre in moving from one extreme position to the other.

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TopNewestIt's not a problem posted on Brilliant, otherwise I would have shut it down already. I am unaware if it's a current contest problem.

The statement of the problem could be better explained.

A quick search shows that this problem has used in several contexts, and I see an attribution to Loney [problem 81 of this pdf]. – Calvin Lin Staff · 4 years, 6 months ago

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its not a problem posted on brilliant.......... but is there a rule that we need to post only brilliant questions :(((( – Ayushi Agrawal · 4 years, 6 months ago

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It just seems a lot like a problem that would be on Brilliant. The rules are, you cannot post a problem on a current Brilliant problem set, your homework, or questions on an exam/test. We also ask that you cite a source when you post word for word a problem that you did not make up yourself.

To avoid confusing people a good practice would be to state in the discussion body where you found the problem, and why you think it is interesting. This context, will make people more excited to solve the problem. People are not just interested in solving the problem they are also interested in why you think it is cool and wanted to share it:) – Peter Taylor Staff · 4 years, 6 months ago

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I'm now wondering either this is a contest problem or this week's Brilliant Problem. (It is posted two times already.) – Zi Song Yeoh · 4 years, 6 months ago

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