Parallel Lines and Transversals

1
Parallel Lines and Transversals

• Parallel - Two lines are parallel if and only if
  they lie in the same plane and do not intersect.
  Two planes are parallel if and only if they do
  not intersect. Segments or rays are parallel if
  and only if the lines that contain them are
  parallel.
• Transversal A line that intersects two or more
  lines in a plane at different points.

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Example 1-1e
Use the figure to name each of the following.
Answer plane XYZ
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Example 1-2e
HIKING A group of nature trails is shown.
Identify the sets of lines to which each given
line is a transversal.
Answer lines c, d, e, f
Answer lines c, d, e, f
Answer lines a, b, d, e, f
Answer lines a, b, c, e, f
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Parallel Lines and Transversals

• Interior angles - ?2, ?3, ?6, and ?7
• Exterior angles - ?1, ?4, ?5, and ?8
• Corresponding angles - A pair of nonadjacent
  angles - one exterior, one interior - both on the
  same side of the transversal.
• ?1 and ?3, ?2 and?4,
• ?5 and ?7, ?6 and ?8

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Parallel Lines and Transversals

• Alternate exterior angles - A pair of nonadjacent
  angles, both exterior angles, on opposite sides
  of the transversal.
• ?1 and ?8, ?4 and ?5
• Same side (consecutive) interior angles - A pair
  of nonadjacent angles, both interior angles, on
  the same side of the transversal.
• ?2 and ?3, ?6 and ?7

Alternate interior angles - A pair of nonadjacent
angles, both interior angles, on opposite sides
of the transversal. ?2 and ?7, ?6 and ?3
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Example 1-3g
Identify each pair of angles as alternate
interior, alternate exterior, corresponding, or
consecutive interior angles.
Answer consecutive interior
Answer corresponding
Answer alternate exterior
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Example 1-3g
Identify each pair of angles as alternate
interior, alternate exterior, corresponding, or
consecutive interior angles.
Answer alternate interior
Answer corresponding
Answer alternate exterior