Problem #PRU-35238

Problems Geometry Plane geometry Triangles Types of triangles Equilateral triangle Combinatorics Painting problems Methods Pigeonhole principle Pigeonhole principle (finite number of poits, lines etc.)
 12–14  3.0

Problem

A Cartesian plane is coloured in in two colours. Prove that there will be two points on the plane that are a distance of 1 apart and are the same colour.