MathDB
PB//DQ if AQ//CP and AB// CD (trapezoid ABCD)

Source: Netherlands - Dutch NMO 1971 p1

January 28, 2023
geometrytrapezoidparallel

Problem Statement

Given a trapezoid ABCDABCD, where sides ABAB and CDCD are parallel; the points PP on ADAD and QQ on BCBC lie such that the lines AQAQ and CPCP are parallel. Prove that lines PBPB and DQDQ are parallel.