Circumference of the circle and the radian

http://dmentrard.free.fr/GEOGEBRA/Maths/rad1MD.html
[url=http://dmentrard.free.fr/GEOGEBRA/Maths/rad1MD.html]http://dmentrard.free.fr/GEOGEBRA/Maths/rad1MD.html[/url]

Information: Circumference of the circle and the radian