Angles:- Angle is the union of two rays with a common end point.
* When two rays in a plane meet at a point, an angle is formed.
* The two rays forming an angle are called the arms or sides of the angle.
The amount of rotation performed by a ray with its end point fixed either in clockwise or anti clockwise direction is also be called as “Angle”.
* The ray which is in a fixed position is called the initial ray and the position of the rotating ray is called the terminal ray.
* The common end point of the two rays forming an angle is called the vertex of the angle.
An angle whose measure is more than 00 but less than 900 is called an Acute angle.
An angle whose measure is 900 is called an Right Angle:
An right angle is exactly one quarter of a revolution.
An angle whose measure is more than 900 but less than 1800 , is called an Obtuse Angle.
An angle whose measure is 1800, is called an Straight angle.
A straight angle is exactly one half of a revolution.
An angle whose measure is more than 1800 but less than 3600 is called an Reflex Angle.
An angle whose measure is 3600, is called an Complete Angle
If the terminal ray coincides with the initial ray after one complete rotation. Then the angle formed is called a complete angle.
If the terminal ray coincides with the initial ray, without any rotation. Then the angle formed is called ‘zero angle’.
If the measure of the angle is 00 it is called a zero angle.