Backpage: My Favorite Lesson
The Back Page: My Favorite Lesson - Slopes of Parallel and Perpendicular Lines: A Visual Justification

Patricia Wallace-Gomez 

May 2011, Volume 104, Issue 9, Page 728

Abstract:
Two visual proofs of the relationship of the slopes of parallel and perpendicular lines are shown.

Keywords:
Linear
Article
Grades 9-12
Teacher
Representation
Slope
Transformations