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2. Angle: An angle is formed when two rays originate from the same endpoint.

Angle ABC is denoted by ∠ABC

The rays ( and ) making an angle are called the arms of ∠ABC.
The end point (B) is called the vertex of ∠ABC.

3. Types of Angles: There are different types of angles such as acute angle, right
angle, obtuse angle, straight angle and reflex angle.
(i) Acute angle: An acute angle is an angle which is less than 90°.
Acute angle : 0° < x < 90°.

(ii) Right angle: A right angle is an angle which is equal to 90°.
Right angle : y = 90°