- Books Name
- CBSE Class 6 Mathematics Book

- Publication
- Param Publication

- Course
- CBSE Class 6

- Subject
- Mathmatics

**Kinds of angle**

Angles are classified according to their degree measure.

**(i) Acute Angle :** An angle smaller than a right angle is called an acute angle.

**(ii) Right Angle : ** An angle which measures 90º is called a right angle. In Fig. ABC is a right angle.

**(iii) Obtuse Angle :** If an angle is larger than a right angle, but less than a straight angle, it is called an obtuse angle.

**(iv) Straight Angle : **An angle which measures 180° is called a straight angle in figure. *∠*ABC is a straight angle.

**(v) Reflex Angle :** An angle which measures greater than 180° and less than 360° is called a reflex angle. *∠*AOC is a reflex angle.

**(vi) Complete Angle :** An angle which measures 360° is called a complete angle. *∠*AOB is complete angle.

**Perpendicular lines **

When two lines intersect and the angle between them is a right angle, then the lines are said to be perpendicular. If a line AB is perpendicular to CD, we write AB *⊥*CD.

**Perpendicular bisector **

A line perpendicular to the given line segment as well as bisects it, is called perpendicular bisector. Line LM is perpendicular bisector of line segment AB.