IMO 2006 Shortlist G5
In triangle ABC, let J be the centre of the excircle tangent to side BC at A1 and to the extensions of sides AC and AB a...
Category: Geometry
Problem
In triangle ABC, let J be the centre of the excircle tangent to side BC at A1 and to the extensions of sides AC and AB at B1 and C1, respectively. Suppose that the lines A1B1 and AB are perpendicular and intersect at D. Let E be the foot of the perpendicular from C1 to line DJ. Determine the angles ∠BEA1 and ∠AEB1. (Greece)