[list=1][*]Create point A ([icon]/images/ggb/toolbar/mode_complexnumber.png[/icon]but it has an A not a Z)[/*][*]Create line BC. ([icon]/images/ggb/toolbar/mode_join.png[/icon])[/*][*]Reflect A across line BC ([icon]/images/ggb/toolbar/mode_mirroratline.png[/icon], then click Point A and then click line BC).[/*][*]Create a segment between A and A' ([icon]/images/ggb/toolbar/mode_join.png[/icon] then [icon]/images/ggb/toolbar/mode_segment.png[/icon] then click on points A and A').[/*][*]Label the intersection of segment AA' and line BC ([icon]/images/ggb/toolbar/mode_complexnumber.png[/icon] then [icon]/images/ggb/toolbar/mode_intersect.png[/icon] then click on the segment and and the line). [/*][*]Move Point A around. What do you notice about A, A', and line BC?[/*][*]Use the measures buttons to confirm your conjectures.[/*][/list][list][*]To measure a segment, choose [icon]/images/ggb/toolbar/mode_angle.png[/icon]then [icon]/images/ggb/toolbar/mode_distance.png[/icon] then click on both endpoints of the segment).[/*][*]To measure an angle, click [icon]/images/ggb/toolbar/mode_angle.png[/icon] then three points.[/*][/list]