Area of the circle explained with a cake

http://dmentrard.free.fr/GEOGEBRA/Maths/circlecakeMD.html
[url=http://dmentrard.free.fr/GEOGEBRA/Maths/circlecakeMD.html]http://dmentrard.free.fr/GEOGEBRA/Maths/circlecakeMD.html[/url]

Information: Area of the circle explained with a cake