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MathNet 2014 Question 43

Math Olympiad Vault · MathNet 2014

Question 43

The internal angle bisectors at vertices $A$ and $B$ of triangle $ABC$ meet the opposite sides at $D$ and $E$, respectively. A rhombus is inscribed in quadrilateral $ABDE$ so that exactly one vertex of the rhombus lies on each side of the quadrilateral. If $\angle BAC=\alpha$ and $\angle ABC=\beta$, prove that at least one angle of the rhombus is no greater than $\max\{\alpha, \beta\}$.

(Dušan Đukić)