MathDB
integer right triangle on lattice points has incenter a lattice point

Source: 1991 German Federal - Bundeswettbewerb Mathematik - BWM - Round 1 p3

November 20, 2022
geometryincenterlattice points

Problem Statement

In a plane with a square grid, where the side length of the base square is 11, lies a right triangle. All its vertices are lattice points and all side lengths are integer. Prove that the center of the incircle is also a lattice point.