Angles

Fig-1 Positive Angle

Fig-2 Negative Angle

An angle is formed when two rays are joined together at a common point. The common point is called as node or vertex. An angle is a measure of rotation of a given ray about its vertex. Original ray is called as initial side and the final position of the ray after rotation is called as terminal side of the angle. The point of rotation is called as vertex. Angle is said to be positive if the direction of rotation is anticlockwise (Fig-1), angle is said to be negative if the direction of rotation is clockwise.(Fig-2),