9 Point Circle Action
For every triangle that exists, there is a very special circle that passes through 9 points. Some of these points lie on the triangle itself, and some do not.
The applet below will informally illustrate the construction of a triangle's 9-point circle.
Be sure to change the locations of the triangle's BIG WHITE VERTICES each time before re-sliding the slider. It would also be wise to alter the locations of these vertices after you've constructed this 9-point circle.