1) Use the Line tool[icon]/images/ggb/toolbar/mode_join.png[/icon] to draw a line through the center of the circle and the given point on the circle.[br]2) Use the Intersect tool[icon]/images/ggb/toolbar/mode_intersect.png[/icon] to mark where this line intersects the circle.[br]3) Create a line perpendicular to this one that goes through the center of the circle.[br]4) Use the Intersect tool[icon]/images/ggb/toolbar/mode_intersect.png[/icon] to mark where this line intersects the circle.[br]5) Use the Segment tool[icon]/images/ggb/toolbar/mode_segment.png[/icon] to connect these four points, creating a square inscribed in the circle.[br]6) Create the perpendicular bisectors for two adjacent sides of this square.[br]7) Use the Intersect tool[icon]/images/ggb/toolbar/mode_intersect.png[/icon] to mark where these two new lines intersect the circle.[br]8) Use the Polygon tool[icon]/images/ggb/toolbar/mode_polygon.png[/icon] to connect the eight points on the circle to create an octagon.[br]9) Use the Distance tool[icon]/images/ggb/toolbar/mode_distance.png[/icon] and Angle Measure tool[icon]/images/ggb/toolbar/mode_angle.png[/icon] to verify that this is a regular octagon.