High Quality Content by WIKIPEDIA articles! Rational trigonometry is a recently introduced approach to trigonometry that eschews all transcendental functions (such as sine and cosine) and all proportional measurements of angles. In place of angles, it characterizes the separation between lines by a quantity called the "spread", which is a rational function of their slopes. In place of the classical transcendental functions, it introduces a number of "laws" between the lengths and spreads of lines bound by various geometric configurations, notably triangles.