Problem B. 4642. (September 2014)

B. 4642. Given that no three of five points in the plane are collinear, prove that there are at most seven acute-angled triangles among the triangles determined by the five points.

(4 pont)

Deadline expired on October 10, 2014.

Statistics:

172 students sent a solution.
4 points:	95 students.
3 points:	24 students.
2 points:	21 students.
1 point:	16 students.
0 point:	16 students.

Problems in Mathematics of KöMaL, September 2014