Trigonometry

Trigonometric Identities and Formulas
There are three systems of measuring Angles-
1. Circular System
Unit of Measurement is radian.
180 degree = π radians
2. Sexagesimal System (English System)
Right angle is divided into 90 equal parts called degree.
Unit of Measurement is degree.
3. Centesimal or French System
Right angle is divided into 100 equal parts.