regular pentagon

Each of the images below is a link to a step-by-step geogebra applet through which it is possible to move forwards and backwards in the construction, or watch how the construction is solved in a short animation. The blue “circular” points in some applets are movable.

These applets are gathered in this this geogebra book.


regular pentagon inscribed in a circle #01

regular pentagon inscribed in a circle #02

regular pentagon inscribed in a circle #03

(adapted from the marvellous book published in 1947, by A. A. Ferreira de Macedo, “A Geometria ao Alcance de toda a Gente”).

regular pentagon inscribed in a circle #04

regular pentagon give the edge lenght