Chapter Three:  
Parallel and Perpendicular Lines

Geometry   Notes

Chapter  3

Section  3.1
Section  3.2
Section  3.3
Section  3.4
Section  3.5
Section  3.6
Section  3.7

Geometry Contents

Take notes on the following topics.

Section 3-6  Slopes of Parallel and Perpendicular Lines

Slopes of Parallel Lines

If two nonvertical lines are parallel, then their slope are equal.
 

If the slopes of two distinct nonvertical lines are equal, then the lines are parallel.

Any two vertical lines are parallel.

Slopes of Perpendicular Lines

If two nonvertical lines are perpendicular, then the product of their slopes is   -1.
 

If the slopes of two lines have a product of  -1, then the lines are perpendicular.

 

Any horizontal line and vertical line are perpendicular.