Recall that to "bisect" something is to split it into two congruent pieces. In order to bisect a line segment, we must create its [b]perpendicular bisector[/b]. This is a line or line segment which splits the original segment into two congruent pieces AND is perpendicular to the original line segment.[br][br]1) Draw a circle centered at A with radius AB by choosing the Compass tool[icon]https://www.geogebra.org/images/ggb/toolbar/mode_compasses.png[/icon], then clicking A, then B, then A again.[br]2) Draw a circle centered at B with radius AB by clicking A, then B, then B again.[br]3) Use the Intersect tool[icon]https://www.geogebra.org/images/ggb/toolbar/mode_intersect.png[/icon] to create points where the two circles meet by clicking one circle and then the other. NOTE: There are TWO intersection points.[br]4) Use the Line tool[icon]https://www.geogebra.org/images/ggb/toolbar/mode_join.png[/icon] to draw the perpendicular bisector connecting those two points.[br]5) The midpoint of AB is the intersection of AB and the line you just made. Mark the midpoint. [br]6) You can verify that the lines are perpendicular by using the Angle Measure tool[icon]https://www.geogebra.org/images/ggb/toolbar/mode_angle.png[/icon]. Click point B, then M, then the intersection point above the original segment. This should be 90 degrees.[br]7) You can verify that AB is bisected by using the Segment Measure tool[icon]https://www.geogebra.org/images/ggb/toolbar/mode_distance.png[/icon]. [br]