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MathNet 2013 Question 100

Math Olympiad Vault · MathNet 2013

Question 100

Let $N$ be the foot of the altitude from $C$ to the hypotenuse $\overline{AB}$ of a right triangle $ABC$. The angle bisectors of the angles $\angle NCA$ and $\angle BCN$ intersect the segment $\overline{AB}$ in the points $K$ and $L$ respectively. If $S$ and $T$ are incircles of the triangles $BCN$ and $NCA$ respectively, prove that the quadrilateral $KLST$ is cyclic. (from an article of A. Marić)