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.
CBSE Class 9: Heron’s Formula - Applications of Heron’s Formula
CBSE Class 9: Lines and Angles - Types of Angles