a parallel line & mid-points

Line EF is a parallel line to line BC.Point A and D are on line EF.Point M and N are the mid-points.


Move point D to find the geometric quality of the lengthes (AD, BC, MN) .

@You can also move points (A, B, C, D, E, F) on CABRI.

@Download CABRIU data (d24) from here.