This applet can be used as an enrichment topic after a lesson on "triangle centers".
You can make your own worksheet for the students to organize their observations as the triangle changes: acute scalene triangle, right scalene triangle, right isosceles triangle, equilateral triangle, obtuse triangle, etc...
See also a related applet for "Euler line" as another enrichment topic.
http://tube.geogebra.org/student/m1451381
