Bellwork

1
Bellwork
No Clickers

• Solve
• What is the reciprocal of ?
• Jenny was thinking of a number. The product of
  her number and 6 is -1. What was her number?

2
Bellwork Solution

• Solve

3
Bellwork Solution

• What is the reciprocal of ?

4
Bellwork Solution

• Jenny was thinking of a number. The product of
  her number and 6 is -1. What was her number?

5
Find and Use Slopes of Lines

• Section 3.4

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The Concept

• Today and tomorrow will be a lot of review of a
  topic that we spent considerable time with in
  Algebraslope
• We are revisiting this topic because as we begin
  to attach geometric shapes to the coordinate
  plane, we utilize slope to identify important
  aspects of the shapes

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Slope

• Lets test your knowledge.
• Slope is a measure of?
• Slope can either be positive, negative, 0 or
  undefined. What kind of line is associated with
  each?
• What is the equation for slope of a line
• The slopes of parallel lines have this kind of
  relationship
• The slopes of perpendicular lines have this kind
  of relations

Slope is a ratio of how much a line rises for how
much it runs
Positive moves up Negative moves down 0
horizontal undefined vertical
The slope is the same
The slopes are negative reciprocals of each other
Axis of symmetry
Vertex
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Slope Postulates

• Postulate 17 Slopes of Parallel Lines
• In a coordinate plane, two nonvertical lines are
  parallel if and only if they have the same slope
• Any two vertical lines are parallel
• Postulate 18 Slopes of Perpendicular Lines
• In a coordinate plane, two nonvertical lines are
  perpendicular if and only if the product of their
  slopes is -1
• Horizontal lines are perpendicular to vertical
  lines

Vertex
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Homework

• 3.4
• 1-15, 16-26 even, 33-36, 39, 40

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Practical Example

• In 2000, a business made a profit of 8500. In
  2006, the business made a profit of 15,400.
  Find the average rate of change in dollars per
  year from 2000 to 2006.

Axis of symmetry
Vertex
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Most Important Points

• Slope definition
• Equation for slope
• Different designations for slope
• Relationship between slopes and parallel and
  perpendicular lines