The Journal of Online Mathematics and Its Applications

Volume 7. September 2007. Article ID 1606

How does this button work?
GeoGebra from the point of view of Euclidean Constructions

Chris Sangwin

Author Information

Christopher J. Sangwin is a lecturer in the School of Mathematics at the University of Birmingham, UK. You may contact him by e-mail, or visit his website for more information about his projects and research interests.


It is not clear at the outset in dynamic geometry how the buttons relate to each other, or that the possibility of catastrophic circularity can be avoided. This was something previous writers such as Euclid were at pains to avoid. Hence we ask "how does this button work?". Or, put another way, this article is one attempt to examine the dynamic geometry package GeoGebra from the point of view of Euclidean Constructions.

Technologies Used in This Article



  1. Introduction
  2. Buttons in GeoGebra
  3. Theorems
  4. The case of conics
  5. Missing buttons?
  6. Conclusions and References