# Lines and Angles Class 9 Notes Maths - Chapter 6

## Chapter: 6

## What Are Lines And Angles ?

## Collinear And Non-collinear Points

• If three or more points lies on the same line then they are called collinear points.

• It the points are not collinear then we can say they are non-collinear points.

• Two points are always collinear.

## Parallel And Intesecting Lines

• Two lines are said to be intersecting, if they intersect each other at one point.

• Lines which do not intersect are called parallel lines.

**An Important Fact**

Lines which are parallel to the same line, are parallel to each other.

## Some Important Facts

• If two lines intersect each other, then the vertically opposite angles are equal.