Editing Barycentric coordinate system (section)

===Conversion between barycentric and trilinear coordinates===
A point with [[trilinear coordinates]] ''x'' : ''y'' : ''z'' has barycentric coordinates ''ax'' : ''by'' : ''cz'' where ''a'', ''b'', ''c'' are the side lengths of the triangle.  Conversely, a point with barycentrics <math>\lambda_1 : \lambda_2 : \lambda_3</math> has trilinears <math>\lambda_1/a:\lambda_2/b:\lambda_3/c.</math>