x^3- (a^2 + b^2 + c^2)x -2abc = 0 for quadrilateral inscribed in semicircle
Source: 2010 Saudi Arabia Pre-TST 2.4
December 28, 2021
semicircleinscribedgeometry
Problem Statement
Let be a quadrilateral inscribed in a semicircle of diameter . Denote , , . Prove that .