Play around with the constructed Proposition 1 to ensure it is equalaterial. You will need to download the file to your local system (http://www.geogebratube.org/files/material-5352.ggb) to make your own construction. Delete the existing objects or choose File --> New to start over. You can turn off axis display under View --> Axes (twice to uncheck).
Save your version of Proposition 1 as a .GGB to your local system.