<BCP < <BHP wanted, parallelogram related to orthocenter
Source: Ukrainian Geometry Olympiad 2020, IX p3, X p2
April 27, 2020
geometryparallelogramorthocenteranglesangle inequalities
Problem Statement
Let be the orthocenter of the acute-angled triangle . Inside the segment arbitrary point is selected. Let be such that is a parallelogram. Prove that .