120 unit squares in 20x25 rectangle, circle of diameter 1
Source: Polish MO Second Round 1972 p2
September 8, 2024
geometryrectanglecombinatoricscombinatorial geometry
Problem Statement
In a rectangle with sides of length 20 and 25 there are 120 squares of side length 1. Prove that there is a circle with a diameter of 1 contained in this rectangle and having no points in common with any of these squares.