Verhoudingen

Uitleg

https://www.youtube.com/watch?time_continue=17&v=XLKARgQMSBg
https://www.youtube.com/watch?time_continue=20&v=yLAguq36J68
https://www.youtube.com/watch?time_continue=18&v=dnWADuMk_9I
https://youtu.be/7yDc4JWVsNc
https://youtu.be/oKg0e5rBdag
https://youtu.be/E0XxafbssWI
https://youtu.be/YnkyhuJ0V3U
https://youtu.be/ABNYp_OvZek