IMO Shortlist 1996 problem G1


Kvaliteta:
  Avg: 5.0
Težina:
  Avg: 5.0
Dodao/la: arhiva
April 2, 2012
LaTeX PDF
Let ABC be a triangle, and H its orthocenter. Let P be a point on the circumcircle of triangle ABC (distinct from the vertices A, B, C), and let E be the foot of the altitude of triangle ABC from the vertex B. Let the parallel to the line BP through the point A meet the parallel to the line AP through the point B at a point Q. Let the parallel to the line CP through the point A meet the parallel to the line AP through the point C at a point R. The lines HR and AQ intersect at some point X. Prove that the lines EX and AP are parallel.
Source: Međunarodna matematička olimpijada, shortlist 1996