MathDB
point divides quadrilateral into four equal triangles

Source: Yugoslav TST 1981 P2

May 29, 2021
geometry

Problem Statement

Suppose that there is a point SS inside a quadrilateral ABCDABCD such that segments SA,SB,SC,SDSA,SB,SC,SD divide the quadrilateral into four triangles of equal areas. Prove that one of the diagonals of the quadrilateral bisects the other one.