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Parallel lines and Transversals. Sec 3.1 Sol:G.3a. Parallel Lines. Parallel lines are coplanar lines that do not intersect. Arrows are used to indicate lines are parallel. The symbol used for parallel lines is ||. In the above figure, the arrows show that line AB is parallel to line CD.
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Parallel lines and Transversals Sec 3.1 Sol:G.3a
Parallel Lines • Parallel lines are coplanar lines that do not intersect. • Arrows are used to indicate lines are parallel. • The symbol used for parallel lines is ||. In the above figure, the arrows show that line AB is parallel to line CD. With symbols we denote, . Lesson 2-3: Pairs of Lines
OBLIQUE LINES • Oblique lines are lines that intersect, but do NOT form a right angle. • m n Lesson 2-3: Pairs of Lines
Skew Lines and Parallel Planes Definition: Skew lines are lines that are non-coplaner and do not intersect. Ex: What lines are skew to ? Definition: Parallel planes are planes that do not intersect. Ex : Name a set of parallel planes.
Transversal • Definition: A line that intersects two or more lines in a plane at different points is called a transversal. Note: Transversals intersects do not always have to be Parallel. • When a transversal t intersects line n and m, eight angles of the following types are formed: Exterior angles Interior angles Consecutive interior angles Alternative exterior angles Alternative interior angles Corresponding angles t m n Lesson 2-4: Angles and Parallel Lines
Exterior and Interior Angles • Exterior Angles: Angles that are on the “outside” of the two “clusters” • Interior Angles: Angles that are in the “middle “ of the two “clusters”
Consecutive Interior Angles • Consecutive Interior Angles: (Same-side Interior Angles) • Are on the same side of the transversal. • On the inside.
Alternate Exterior and Alternate Interior Angles • Alternate Exterior Angles: • Are on the opposite sides (or they alternate sides) of the transversal. • Are on the outside. • Alternate Interior Angles: • Are on the opposite sides of the transversal. • Are on the inside.
Corresponding Angles • Corresponding Angles: • Occupy the same place in the different clusters.
m t 1 8 l 5 10 2 4 11 7 12 6 9 3 Identify each pair of angles as Alt. interior, Alt. exterior, Corresponding or Consecutive interior angles. a. b. c. d. e. f. Identify all pairs of vertical angles. Identify all linear pairs.
Assignment CW: 59-60 1-12, 14, 16-23,27 Hw: pg 144-145 11-29, 37-42