The regular nonagon


  • Sotìris Goudouvàs 1st Lyceum of Argyroupolis


Normal nonagon, geometric construction, cyclotomy, regular star nonagon


In the present work we study the construction of the regular nonagon, ie the division of the circle into nine equal parts. We prove that the construction with ruler and compass is impossible and we present the two regular star nonagons.

Author Biography

Sotìris Goudouvàs, 1st Lyceum of Argyroupolis

Sotiris Goudouvas obtained a degree in mathematics from the University of Ioannina (Greece) and later obtained a degree in Civil Engineering from EM of Athens.
He holds two Master's Degrees in Teaching Methodology and History of Mathematics from the University of Athens and Modern and Contemporary History from Panteion University of Athens.
He is the author of the book Geometric Routes (2015) and has written various articles in mathematical journals on the History of Mathematics and Geometry.
Is a researcher in didactics of Geometry.
He works as a Mathematics teacher at the 1st Lyceum of Argyroupolis (Greece).


Gountouvas Sotiris, (2017). Geometrical Routes, Athens.

Gountouvas Sotiris, (2019). The Regular Heptagon, EDiMaST, 5, 689-695.

Stamatis Evangelos, (1975). Euclid’s Elements (???????? ?????????), Athens.

Tsimbourakis Demetrios, (1985). Geometry in ancient Greece, Athens.

Fraleigh John, (1989). A first course in Abstract Algebra, Addison-Wesley Publishing Company, NY.

Sir Tomas L. Heath, (2001). A History of Greek Mathematics (translated in Greek), K.E.E?.??, Athens.




How to Cite

Goudouvàs, S. (2020). The regular nonagon. EDiMaST: Experiences of Teaching With Mathematics, Sciences and Technology, 6, 1–7. Retrieved from



Experiences & Research Articles