IMO Shortlist 1982 problem 2
Dodao/la: arhiva2. travnja 2012.
be a convex polygon in the plane and suppose that
is positioned in the coordinate system in such a way that
denote the quadrants of the plane. Prove that if
contains no nonzero lattice point, then the area of
is less than
Izvor: Međunarodna matematička olimpijada, shortlist 1982