Construct the Midpoint of a Segment
1) Plot two points, A & B
2) Use segment tool to construct Segment AB
3) Use circle to draw Circle A with radius AB
4) Use circle to draw Circle B with radius BA
5) Use point tool the mark intersections of the circle; Points C & D
6) Use the segment tool to make Segment CD
7) Use point tool to mark the Midpoint of Segment AB
Use the style bar to change all construction lines to dotted lines; you can also change their colors.