MathDB
China Mathematical Olympiad 1986 problem4

Source: China Mathematical Olympiad 1986 problem4

January 18, 2014
geometrygeometry unsolved

Problem Statement

Given a ABC\triangle ABC with its area equal to 11, suppose that the vertices of quadrilateral P1P2P3P4P_1P_2P_3P_4 all lie on the sides of ABC\triangle ABC. Show that among the four triangles P1P2P3,P1P2P4,P1P3P4,P2P3P4\triangle P_1P_2P_3, \triangle P_1P_2P_4, \triangle P_1P_3P_4, \triangle P_2P_3P_4 there is at least one whose area is not larger than 1/41/4.