Consider parallelogram with . Point on and point on are marked such that there exists a circle passing through and a circle passing through . If partition into segments in that order, with lengths , respectively, compute .
Solution
We want to find . So, let intersect at . It is clear that . However, we can show by angle chase that : This means that partitions and into the same proportions, i.e. 200 to 80 . Now, let to make computation simpler. is on the radical axis of and its power respect to the two circles can be found to be However, there is now for which by similarity. This means . Notably, we want to find , which is just
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