Geometry 3.1

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• Geometry 3.1
• Big Idea Identify pairs of lines and angles

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Vocabulary

• Parallel Lines
• Two lines that do not intersect and are coplanar.

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• Skew Lines
• Two lines that do not intersect and are not
  coplanar.

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• Parallel Planes
• Two planes that do not intersect.
• Ex plane RSTU plane WXYZ

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• Note a small triangle (like an arrow, pointed
  in one direction of a line) is used to indicate
  that lines are parallel (our book uses red color
  to denote this) the arrow is on each line, not
  at the end

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Postulates

• Postulate 13Parallel Postulate
• If there is a line and a point not on the line,
  then there is exactly one line through the point
  to the given line.
• ? P
• m

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• Postulate 14Perpendicular Lines
• If there is a line and a point not on the line,
  then there is exactly one line through the point
  - to the given line.
• ? P
• m

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More Vocabulary

• Transversal
• A line that intersects 2 or more coplanar lines
  at different points.

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• Corresponding Angles on same side of transversal
  with same relationship (on top or on bottom) to
  other 2 lines (2 6), others?

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• Alternate Interior Angles
• Angles that lie between the 2 lines on opposite
  sides of the transversal (3 5), others?

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• Alternate Exterior Angles
• Angles that lie outside the 2 lines on opposite
  sides of the transversal.
• (2 8), others?

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• Consecutive Interior Angles
• Angles that lie between the 2 lines on the same
  side of the transversal.(4 5 ),others?

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Example Identify all pairs of angles of the
given type.

• Corresponding
• Alternate Interior
• Alternate Exterior
• Consecutive interior
• Vertical

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