3 of 4 sticks are sidelengths (2017 Adygea Teachers' Geometry Olympiad p3 RU)
Source:
June 21, 2020
geometrySides of a triangle
Problem Statement
Jack has a quadrilateral that consists of four sticks. It turned out that Jack can form three different triangles from those sticks. Prove that he can form a fourth triangle that is different from the others.