1. 1.5: Parallel and Perpendicular Lines
WELCOME
1.5: Parallel and Perpendicular Lines

2. Chapter 1 Section 5

5. Perpendicular / Parallel
Perpendicular Lines:
Lines that intersect to form a right (90°) angle
m f
“m is Perpendicular to f ”
Parallel Lines:
Coplanar lines that never intersect
p ‖ m
“p & m are parallel” p f m m

7. Parallel Slope
In a coordinate plane, two nonvertical lines are parallel if they have the same slope

8. Perpendicular Slope
In a coordinate plane, two nonvertical lines are perpendicular if they have opposite reciprocal slopes
(Slopes are opposite & flipped!!)