When drawing the three midsegments on the board, I’ll ask the class to take a moment and observe the illustration on the board and the one I had them do on their paper.What do you notice about the midsegments? What do they do to the traingle?
I make sure that students raise their hands rather than blurt out the obvious: That the triangles form four “baby congruent traingles.” This allows time for the less bright students to observe and discover on their own without being told the phenomenon. After enough time has ellapsed and more and more students see it, I’ll allow one to explain his/her findings. When piggy-backing off his/her findings and explaining it myself, I’ve found it always gives the students a good laugh to actually refer to the four triangles as “babies” and to the bigger triangle as “the big mama triangle.”