each image below links to a step‑by‑step GeoGebra applet, where you can move forwards and backwards through the construction or watch a short animation of how it unfolds. in some applets, the blue circular points are movable. these applets are also collected in 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 marvelous book A Geometria ao Alcance de toda a Gente (1947), authored by A. A. Ferreira de Macedo.
regular pentagon inscribed in a circle #04
regular pentagon given the edge length
moving geometry 