Romanian National Olympiad 2018 - Grade 9 - problem 4
Source: Romania NMO - 2018
April 12, 2018
geometrycombinatorics
Problem Statement
Let and consider a circle of length along with points on the circle which divide it into arcs: of them have length some other have length and the remaining have length
Prove that among these points there must be two such that the line that connects them passes through the center of the circle.