# Definition of a perpendicular line

When two lines intersect and form a 90° angle, also called a right angle, then they are said to be perpendicular.

**⊥**is used to represent perpendicular

Perpendicular lines intersect at right angles ( 90 degrees )

A straight line has a measure of 180 degrees therefore, all four of the angles will be 90 degrees when the lines are perpendicular.

## Examples of perpendicular lines

## Parallel lines

## Parallel lines

## How do you determine if two lines are parallel or perpendicular?

**Given two lines. One line passes through (-3,0) (1.1), the other line passes through (0,3) (2,-5)**

### Transcript

Welcome to MooMooMath. Today we are going to look at perpendicular lines. What are perpendicular lines or what is perpendicular? Well perpendicular are two lines that intersect at 90 degree angles. So let’s look at a couple of examples of where we will see those. So we have two lines and they are intersecting at 90 degree angles, and I will label it with a little box that represents 90 degrees, and once we know this is 90 degrees we know the other three are 90 degrees because these are lines and lines have a degree of 180 so that would make all four of these 90 degrees. Now let’s look at the two line segments. This angle is 90 degrees and you will often see this in a right triangle. So a right triangle has two segments that are perpendicular and measure 90 degrees. So that is perpendicular lines. Hope this helps