In a Oxy system of coordinates, a point C can be defined by a linear combination of unit vectors on the x-axis and the y-axis. [br]For a point C on a segment |AB| it's useful to define its position relatively to the ending points of the segment. Now Point Vectors to the ending Points A and B are used as unit vectors.[br]The new coordinates of C are defined by the weight of the lenghts of the segments in which C devides the segment |AB|. Therefore we call them [b]barycentric coordinates[/b].