Slope of Lines

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Slope of Lines
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Slope in the Real World

• Surveying
• Building
• Data Analysis
• Sports
• Many other examples
• What other examples can you think of?

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Definition

• Rate of Change Slope rise/run

Run
Rise
Run
Rise
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Positive Slope
Negative Slope
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Finding Slope using Points

• Slope rise/run

Example Find the slope of the line through
A(-2,1) and B(5,7)
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Example

• Find the slope of line segment PQ with points
  P(2,-6) and Q(1,-3)

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Horizontal and Vertical Lines
________

• Horizontal lines have slope of 0
• Vertical lines have an undefined slope

________
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Why is the slope of a horizontal line 0?

• Example
• Find the slope of the line through A(1,2) and
  B(4,2).

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Why is the slope of a vertical line undefined?

• Example
• Find the slope of the line through A(4,2) and
  B(4,-7).

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Parallel Lines

• Two non vertical lines have the same slope if and
  only if they are parallel.
• Why non vertical?

iff both the original and the converse are true.
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Perpendicular Lines

• Lines that cross at right angles.
• OR one slope is the negative reciprocal of the
  other.
• 2 non vertical lines are perpendicular iff the
  product of their slopes is -1.

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More Practice

• Measure up pg 169

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Homework

• Pg. 350 1-14 all, 19-22, 29, 31, 33, 34