IMO Shortlist 1991 problem 5


Kvaliteta:
  Avg: 0,0
Težina:
  Avg: 0,0
Dodao/la: arhiva
2. travnja 2012.
LaTeX PDF
In the triangle ABC, with \angle A = 60 ^{\circ}, a parallel IF to AC is drawn through the incenter I of the triangle, where F lies on the side AB. The point P on the side BC is such that 3BP = BC. Show that \angle BFP = \frac{\angle B}{2}.
Izvor: Međunarodna matematička olimpijada, shortlist 1991