MEMO 2010 ekipno problem 5


Kvaliteta:
  Avg: 2,0
Težina:
  Avg: 4,7
Dodao/la: arhiva
28. travnja 2012.
LaTeX PDF
The incircle of the triangle ABC touches the sides BC, CA, and AB in the points D, E and F, respectively. Let K be the point symmetric to D with respect to the incenter. The lines DE and FK intersect at S. Prove that AS is parallel to BC.
Izvor: Srednjoeuropska matematička olimpijada 2010, ekipno natjecanje, problem 5