# 4 2 Parallel Lines and Transversals 4 2

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4 -2: Parallel Lines and Transversals

4 -2: Parallel Lines and Transversals TRANSVERSAL: A line, line segment, or ray that intersects two or more lines at different points.

4 -2: Parallel Lines and Transversals When a transversal intersects two lines, eight angles are formed. INTERIOR ANGLES: Angles between the two lines 3, 4, 5, 6 ALTERNATE INTERIOR ANGLES: pairs of interior angles that are on opposite sides of the transversal 3 & 5, 4 & 6 CONSECUTIVE INTERIOR ANGLES: pairs of interior angles that are on the same side of the transversal 4 & 5, 3 & 6 EXTERIOR ANGLES: Angles that lie outside the two lines 1, 2, 7, 8 ALTERNATE EXTERIOR ANGLES: pairs of exterior angles that are on opposite sides of the transversal 1 & 7, 2 & 8

4 -2: Parallel Lines and Transversals Identify each pair of angles as alternate interior, alternate exterior, consecutive interior, or vertical 2 & 8 Alternate exterior 1 & 6 Consecutive interior 2 & 4 Vertical 4 & 6 Alternate interior

4 -2: Parallel Lines and Transversals If two parallel lines are cut by a transversal, then… THEOREM 4 -1: alternate interior angles are congruent ( 3 5, 4 6) THEOREM 4 -2: consecutive interior angles are supplementary ( 3 + 6 = 180˚, 4 + 5 = 180˚) THEOREM 4 -3: alternate exterior angles are congruent ( 1 7, 2 8)

4 -2: Parallel Lines and Transversals In the figure, p || q, and r is a transversal. If m 5 = 28, find: m 8 28 m 1 152 m 2 28 m 3 28 m 4 152

4 -2: Parallel Lines and Transversals Assignment Worksheet #4 -2