A little geometry of right triangles --------------------------------------------
A triangle ABC that is right-angled at C has simpler associated geometric features than a general triangle:
\- its orthocenter H is the vertex C;
\- the center O of its circumcircle is simply the midpoint of its hypotenuse, while the circle's radius is half the length of the hypotenuse, namely AB/2 = c/2;
\- the centroid G lies two-thirds of the way along the median CO;