1) Create segment AB [icon]/images/ggb/toolbar/mode_segment.png[/icon][br]2) Create 2 compasses [icon]/images/ggb/toolbar/mode_compasses.png[/icon] with the radius of AB, put 1 center at A and the other at B[br]3) Add points C and D [icon]/images/ggb/toolbar/mode_point.png[/icon] at the intersection [icon]/images/ggb/toolbar/mode_intersect.png[/icon] of the compasses [icon]/images/ggb/toolbar/mode_compasses.png[/icon][br]4) Create line CD [icon]/images/ggb/toolbar/mode_join.png[/icon] and add point E at the intersection [icon]/images/ggb/toolbar/mode_intersect.png[/icon] of CD and AB[br]5) Show that the length of BE and AE [icon]/images/ggb/toolbar/mode_distance.png[/icon]are congruent and that angle E is 90 degrees [icon]/images/ggb/toolbar/mode_angle.png[/icon]