MathDB
any parallelogram can be dissected in n>=4 cyclic quadrilaterals.

Source: 2011 Saudi Arabia Pre-TST November 3.2 https://artofproblemsolving.com/community/c2745403_2011_

January 1, 2022
combinatorial geometrygeometrycyclic quadrilateral

Problem Statement

Prove that for each n4n \ge 4 a parallelogram can be dissected in nn cyclic quadrilaterals.