Basic Parameters of the Orthocenter
The orthocenter of a triangle  is the intersection of its three altitudes.[more]
Let , , be the side lengths opposite the corresponding vertices and , , be the circumradius, inradius and semiperimeter of .
Let , , be the exact trilinear coordinates of and be the sum of the exact trilinear coordinates of the point .
, , are the Conway parameters with ,
is the cevian triangle and pedal triangle of .
You can drag the vertices , and .[less]
A triangle center is said to be even when its barycentric coordinates can be expressed as a function of three variables , , that all occur with even exponents. If the center of a triangle has constant barycentric coordinates, it is called a neutral center (the centroid is the only neutral center). A triangle center is said to be odd if it is neither even nor neutral.
Standard barycentric coordinates of a point with respect to a reference triangle are normalized to have a sum of 1.
 Encyclopedia of Triangle Centers (ETC). https://faculty.evansville.edu/ck6/encyclopedia/etc.html.