Square with 51 points => 3 covered by disk
Source: Bundeswettbewerb Mathematik 1973, round 2, problem 1
May 1, 2007
geometryrectanglecircumcirclecombinatorics proposedcombinatorics
Problem Statement
In a square of sidelength , points are given. Show that there's a disk of radius covering at least of these points.