This sketch simulates how one can experimentally find the median of a carboard triangle by pinning it at one of its vertices, and letting it loose to swing freely, then the median (or 'balance line') will align with a vertical plumb line. By pinning the triangle at the other two vertices, the other two medians can be found, and the intersection of the three medians then gives us the centroid ('balancing point') of the whole triangle.
Instructions: Press the PLAY button to start.Then press in succession, the STEP 1, STEP and STEP 3 buttons. After the triangle and plumb line has come to rest you can also drag the vertices of the triangle or the plumb line. Press the STOP button to reset.
Created with Cinderella by Uli Kortenkamp & slightly modified by Michael de Villiers, March 2009.