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MathNet 2018-part-03 — 181 problems (EN–VI) Question 106

Math Olympiad Vault · MathNet 2018-part-03 — 181 problems (EN–VI)

Question 106

In triangle $ABC$ with $m(\angle A) = 90^{\circ}$ we construct $AD \perp BC$ ($D \in BC$) and the bisector $AE$ ($E \in BC$). Denote by $L$ and $F$ the orthogonal projections of the point $E$ onto the legs $[AB]$ and $[AC]$. Prove that the lines $AD$, $BF$ and $CL$ are concurrent.

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