MathDB

1

Part of 1983 Poland - Second Round

Problems(1)

twice the area of this polygon with latttice points is an integer.

Source: Polish MO Recond Round 1983 p1

9/9/2024
On a plane with a fixed coordinate system, there is a convex polygon whose all vertices have integer coordinates. Prove that twice the area of this polygon is an integer.
geometryanalytic geometrycombinatorial geometrylattice