Angle is defined as intersection of two rays which lie on plane, where rays formed by emanating from vertex. Angle is used to measure the angle of rotation where this measure is the ratio of the length of circular arc to its radius.
SI Unit : Radian
The word angle comes from Latin word (angulus) which means corner. Euclid (Geek Mathematician) defines a plane angle as the inclination to each other, in a plane, of two lines which meet each other, and do not lie straight with respect to each other.
Commonly used symbols (α, Β, γ, θ, Φ, . . . )
Types of Angles:
Zero, acute, right angle, straight, obtuse, perigon and reflex.