1) Plot two points, A & B[br]2) Use segment tool to construct Segment AB[br]3) Use circle to draw Circle A with radius AB[br]4) Use circle to draw Circle B with radius BA[br]5) Use point tool the mark intersections of the circle; Points C & D[br]6) Use the segment tool to make Segment CD[br]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.