[icon]/images/ggb/toolbar/mode_polygon.png[/icon]Construct a triangle. [br][icon]/images/ggb/toolbar/mode_orthogonal.png[/icon]Construct a perpendicular line from any vertex of the triangle to the opposite side. Repeat for all three vertices. [br][icon]/images/ggb/toolbar/mode_intersect.png[/icon]Mark the intersection of the lines using the intersection tool