RU-ALLRUSSIAN 1990 Problem 14
A, B, C are adjacent vertices of a regular 2n- gon and D is the vertex opposite to B (so that BD passes through the center of the 2n- gon). X is a point on the side AB and Y is a point on the side BC so that angle XDY = π/2n. Show that DY bisects angle XYC.
Dataset text NuminaMath olympiads. Quoted with source.
Solutions
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