Bijzondere vierhoeken

Parallellogram https://www.youtube.com/watch?v=Fjb40QHnuUc&t=3s

Ruit https://www.youtube.com/watch?v=MrqHlrAFTqc&t=1s

Trapezium https://www.youtube.com/watch?v=zQBDcLoXh1s

Vlieger https://www.youtube.com/watch?v=Di4df1uo3kg&t=1s