A simple circle question

[soggybread]

Hi guys,

I found this little problem on some website ages go, and was just wondering what you think of it:

http://img354.imageshack.us/img354/9052/cirlce8hk.gif [Broken]

Anyone have any ideas?

 

[AKG]

|OA| = R (since OA is a radius of the big circle)
|OA| = |OM| + |MA| (just look at it)
|MA| = r (since AM is a radius of the small circle)
r² + r² = |OM|² (pythagorean theorem)

 

[soggybread]

interesting, i was thinking that: Line OM + r = R

would that work?

 

[Nimz]

That's what you get when you put AKG's first three lines together into a single equation. Now put that together with the fourth line, and you've got it