Make a rhombus, starting from a segment AB.
Double click in the empty space to open the file in Geogebra. From the view menu, open the construction protocol and study the steps in this construction.

Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and activated. (click here to install Java now)

Arthur Lee, 04/05/2006, Created with GeoGebra