In geometry, an auxiliary angle is an angle that is used to find the measure of another angle. Auxiliary angles are typically used in conjunction with the Law of Sines or the Law of Cosines. In trigonometry, auxiliary angles are used to find the values of trigonometric functions.
Auxiliary angles are important because they can be used to solve a variety of problems in geometry and trigonometry. For example, auxiliary angles can be used to find the measure of an unknown angle in a triangle, or to find the length of a side of a triangle. Auxiliary angles can also be used to solve problems involving circles, such as finding the radius of a circle or the area of a sector.