Inscribing a Square in a Circle
Inscribing a Hexagon in a Circle
http://www.illustrativemathematics.org/illustrations/785
http://www.illustrativemathematics.org/illustrations/786
http://vimeo.com/41125037
Inscrbing an Equilatera in a Circle
http://www.youtube.com/watch?v=bVjPUQElZto
http://www.youtube.com/watch?v=kAevs-sZAEk
http://www.youtube.com/watch?v=Wa3EeTw3-o0
Construct an inscribed Regular Pentagon
Construct an inscribed Regular Hexagon
http://www.mathopenref.com/constinpentagon.html
http://www.mathopenref.com/constinhexagon.html
http://www.mathopenref.com/printinhexagon.html