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Macedonia National Olympiad 2016 Problem 4

Source: Macedonia National Olympiad 2016

April 9, 2016
geometry

Problem Statement

A segment ABAB is given and it's midpoint KK. On the perpendicular line to ABAB, passing through KK a point CC, different from KK is chosen. Let NN be the intersection of ACAC and the line passing through BB and the midpoint of CKCK. Let UU be the intersection point of ABAB and the line passing through CC and LL, the midpoint of BNBN. Prove that the ratio of the areas of the triangles CNLCNL and BULBUL, is independent of the choice of the point CC.