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Bundeswettbewerb Mathematik 1994 Problem 1.3

Source: Bundeswettbewerb Mathematik 1994 Round 1

October 9, 2022
Trianglearea of a trianglegeometrymidpoint

Problem Statement

Given a triangle A1A2A3A_1 A_2 A_3 and a point PP inside. Let BiB_i be a point on the side opposite to AiA_i for i=1,2,3i=1,2,3, and let CiC_i and DiD_i be the midpoints of AiBiA_i B_i and PBiP B_i, respectively. Prove that the triangles C1C2C3C_1 C_2 C_3 and D1D2D3D_1 D_2 D_3 have equal area.