Now that you know how to copy a line segment, you can add and subtract line segments to create new segments (using the Segment Addition Postulate).[br]The top red line is equal to AB + CD.[br]The bottom red line is equal to AB - CD.[br][br]Verify you have added and subtracted correctly by using the Segment Measure tool[icon]https://www.geogebra.org/images/ggb/toolbar/mode_distance.png[/icon] and checking your work with a calculator.