ISL 2011 G7
- Answer
Let be a convex hexagon all of whose sides are tangent to a circle with center . Suppose that the circumcircle of triangle is concentric with . Let be the foot of the perpendicular from to . Suppose that the perpendicular from to intersects the line at a point . Let be the foot of the perpendicular from to . Prove that .
Official text Transcription from NuminaMath olympiads, checked word for word against the official paper. Quoted with source.
Official text: IMO 2011 Shortlist booklet, page 10.
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D L=D J
Solutions
Official solution Solution 1 by the IMO Problem Selection Committee
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