MathDB
Construction of parallelogram in space

Source: Czech and Slovak Olympiad 1956, National Round, Problem 2

August 16, 2022
geometry3D geometryconstructive geometryconstructionparallelogramnational olympiad

Problem Statement

In a given plane ϱ\varrho consider a convex quadrilateral ABCDABCD and denote E=ACBD.E=AC\cap BD. Moreover, consider a point VϱV\notin\varrho. On rays VA,VB,VC,VDVA,VB,VC,VD find points A,B,C,DA',B',C',D' respectively such that E,A,B,C,DE,A',B',C',D' are coplanar and ABCDA'B'C'D' is a parallelogram. Discuss conditions of solvability.