Parallel and Perpendicular Lines

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Parallel and Perpendicular Lines
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Slopes

• Parallel Lines
• The slopes are EQUAL for parallel lines.

• Perpendicular Lines
• The slopes are opposite reciprocals for
  perpendicular lines.

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ExampleIf

• PARALLEL

• PERPENDICULAR

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You Try.......

• If
• find the parallel and perpendicular slopes.

• Parallel
• Perpendicular

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You Try

• If
• find the parallel and perpendicular slopes.

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AnswerRemember

• Parallel

• Perpendicular

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Example

• A. What is the slope of
• ?
• B. What is the parallel slope?
• C. What is the perpendicular slope?

• A.
• B.
• C.

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Example

• Graph the line parallel to
  through (8,2).

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Answer..Parallel to

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Graph .
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Example.

• Graph the line perpendicular to
  
• through (3,2)

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AnswerPerpendicular to
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Graph
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Are the following lines parallel, perpendicular,
or neither?..........

• Answer
• They have the same slope so they are parallel.

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Parallel, Perpendicular, or Neither?

• The slopes are not the same so they are NOT
  parallel.
• The slopes are not opposite reciprocals so they
  are NOT perpendicular.
• They are neither.

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Parallel, Perpendicular, or Neither?......

• You must first change both into slope-intercept
  form.
• Now, you can compare their slopes.

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• They are not the same so they are NOT parallel.
• They are not opposite reciprocals so they are NOT
  perpendicular.
• They are neither.

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Parallel, Perpendicular, or Neither?.....

• Change to slope-intercept form first.
• Compare their slopes.

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• The slopes are opposite reciprocals so they are
  perpendicular.

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Assignment

• Worksheet