MathDB
orthocenter wanted, parallelogram and rhombus related

Source: Tournament of Towns, Junior O-Level Paper, Spring 2020 , p3

June 3, 2020
geometryrhombusparallelogramorthocenter

Problem Statement

Let ABCDABCD be a rhombus, let APQCAPQC be a parallelogram such that the point BB lies inside it and the side APAP is equal to the side of the rhombus. Prove that BB is the orthocenter of the triangle DPQDPQ.
Egor Bakaev