Let's start with the simplest construction.[br][br]Given a line segment AB, copy it to the dotted line as shown in the applet.[br][br][b]Note[/b]: [icon]/images/ggb/toolbar/mode_compasses.png[/icon] is the modern compass and [icon]/images/ggb/toolbar/mode_circle2.png[/icon] is the Euclidean compass.  It is pretty easy to do it using modern compass, isn't it?