100 discs on the plane so that each two of them have a common point ...
Source: Sharygin Geometry Olympiad 2015 Final 9.3
August 1, 2018
geometrycombinatorial geometrycircles
Problem Statement
Let discs lie on the plane in such a way that each two of them have a common point. Prove that there exists a point lying inside at least of these discs.(M. Kharitonov, A. Polyansky)