Herhaling stelling van Pythagoras
https://getalenruimte.digitaal.noordhoff.nl/#/plp/book/da852cfa-55ff-4fcf-896a-c02b757367b8/chapter/dd0cf3c3-cb50-4d82-b8d1-602382ad965c/selection/8f37fecc-dd2f-4407-be68-8babcee2f3aa/theory/2ba61f69-0668-4b81-9dc2-4c90ac7c62b9