CBSE Class 9: Lines and Angles - Basics Terms and Definition

Nov 23, 2017, 10:05 IST

In this video we will learn the basic terms and definitions of the chapter lines and angles from CBSE Class 9 Mathematics. This lecture by the expert teacher will definitely help you build a strong hold over the basics of lines and angles and proceed to the concepts of this topic more efficiently.

Class 9 Llines & Angles: Baisc Terms and definitions

In this video you will learn about the topics basic terms and definitions of the chapter lines and angles.

Collinear Points: Three or more points are said to be collinear, if a line passes through all three points.
Ray: Ray is a part of line, which has one the end point and can be extended indefinitely on the other end.
When two rays have a common initial point they are said to have formed an angle.
The angle is measured in degrees or radians.
Acute angle: If the measure of an angle lies between 0^o and 90^o.
Right angle: If the measure of an angle is equal to 90^o.
Obtuse Angle: If the measure of an angle lies between 90^o and 180^o.
Straight angle: If the measure of an angle is equal to 180^o.
Reflex angle: If the measure of an angle is greater than 180^o but less than 360^o.