The Law of Sines
 Home > Lessons > Law of Sines Search | Updated February 9th, 2018
Introduction
 Equation: The Law of Sines Triangles are a fundamental geometrical shape. Triangles appear within several disciplines, some of which are architecture, engineering, astronomy, and chemistry. This is why mathematicians have studied them and consequently have several relations to enumerate their sides and angles. Here is one such relation.    This is the equation called The Law of Sines.    As it will be thoroughly explained within the next section, this equation is useful when a certain angle and its opposite side are known (and either another side or angle) for a given triangle. If this given information is known, then it is possible to calculate another known angle's opposite side or another known side's opposite angle.    If you are not familiar with how to label a triangle or you have never worked with sine, cosine, or tangent, please read our trigonometry basics section before moving on to the next sections within this page.