MMO 247 Moscow MO 1953 500 points in a convex 1000-gon, triangles
Source:
August 9, 2019
combinatoricscombinatorial geometryTriangles
Problem Statement
Inside a convex -gon, points are selected so that no three of the points — the ones selected and the vertices of the polygon — lie on the same straight line. This -gon is then divided into triangles so that all points are vertices of the triangles, and so that these triangles have no other vertices.
How many triangles will there be?