MathDB
vertices of rectangles inscribed in # lying on AB 1986 Kyiv City MO 8.2

Source:

July 15, 2021
geometryrectangleinscribedparallelogram

Problem Statement

A rectangle is said to be inscribed in a parallelogram if its vertices lie one on each side of the parallelogram. On the larger side ABAB of the parallelogram ABCDABCD, find all those points KK that are the vertices of the rectangles inscribed in ABCDABCD.