This program allows you to experiment with the size
of a triangle and see the resulting incircles, excircles, circumcircles
and ninepoint circles. It is designed to give a pictorial representation
of Feuerbach's Theorem which states that the ninepoint circle of
a triangle T passes through the following nine points: the midpoints
of each side of T, the foot of each altitude of T and the Euler
points of T. Furthermore, the ninepoint circle of T is tangent
to the inscribed circle of T and the three exscribed circles of
T.
