Points covered by strips
Source: Romanian TST 2018 Problem 3 Day 2
May 25, 2020
combinatorial geometrycombinatorics
Problem Statement
Consider a 4-point configuration in the plane such that every 3 points can be covered by a strip of a unit width. Prove that:
1) the four points can be covered by a strip of length at most and
2)if no strip of length less that covers all the four points, then the points are vertices of a square of length