MathDB
only 1 Fermat-Torricelli point inside a triangle

Source: 2022 Viet Nam math olympiad for high school students D1 P1

March 20, 2023
geometry

Problem Statement

Let ABCABC be a triangle with A,B,C<120\angle A,\angle B,\angle C <120^{\circ}.
Prove that: there is exactly one point TT inside ABC\triangle ABC such that BTC=CTA=ATB=120\angle BTC=\angle CTA=\angle ATB=120^{\circ}. (TT is called Fermat-Torricelli point of ABC\triangle ABC)