# How to Know if the Graph Is Parallel, Perpendicular or Neither?

In algebra and geometry, it can be important to determine whether graphs are parallel or perpendicular. Parallel lines never intersect, while perpendicular lines intersect at right angles. Determin...
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http://www.ehow.com/how_8502255_graph-parallel-perpendicular-neither.html

## How to Recognize Perpendicular & Parallel Lines?

By their very definition, perpendicular lines cannot be parallel and parallel lines cannot be perpendicular. Therefore, if you're looking at a series of lines they can either be one or the other, n...
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http://www.ehow.com/how_8058730_recognize-perpendicular-parallel-lines.html

## A Description of Parallel & Perpendicular Lines?

Euclid discussed parallel and perpendicular lines over 2,000 years ago, but the complete description had to wait until Rene Descartes put a framework on Euclidean space with the invention of Cartes...
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http://www.ehow.com/info_8482042_description-parallel-perpendicular-lines.html

## How to Solve Parallel & Perpendicular Lines?

Algebra defines mathematical relationships between unknown variables. The most basic among these are linear relationships, so algebra students need a thorough understanding of linear equations befo...
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http://www.ehow.com/how_8433574_solve-parallel-perpendicular-lines.html

## How to Write a Proof for Perpendicular and Parallel Lines?

Proofs involving parallel and perpendicular lines are actually quite easy to solve. Remember: When it comes to proofs, take what you want the answer to be and do the problem in reverse to create it.

http://www.wikihow.com/Write-a-Proof-for-Perpendicular-and-Parallel-Lines