Take any Triangle with Vertices , , and . Pick a point on the side opposite , and draw a line Parallel to . Upon reaching the side at , draw the line Parallel to . Continue (left figure). Then for any Triangle. If is the Midpoint of , then (right figure).
See also Midpoint, Triangle
References
Madachy, J. S. Madachy's Mathematical Recreations. New York: Dover, pp. 234, 1979.