3.1 Parallel Lines and Transversals Comp book 3.1 Parallel Lines and Transversals Essential Question: How do we use parallel lines and transversals to identify angle measures? Take out 4 different colored pencils from blue box…or your own
Complementary Angles = When sum of two angles equals 90° Comp book Complementary Angles = When sum of two angles equals 90° O R N E
Supplementary Angles = Straight When sum of two angles equals 180° Comp book Supplementary Angles = Straight When sum of two angles equals 180°
Vocabulary P || Q L ⊥ M Comp book Parallel Lines – Lines in the same plane that do not intersect Perpendicular Lines – Intersecting lines whose angle measures 90° P || Q The symbol || means “is parallel to.” L ⊥ M The symbol ⊥ means “is perpendicular to.”
Comp book Transversal: a line that intersects two or more lines. Transversals to parallel lines form special angle pairs. A ll B A B
Adjacent angles: (next door & supplementary = 180) Foldable Adjacent angles: (next door & supplementary = 180) 1 & 2 2 & 3 4 3 1 2 5 6 8 7 3 & 4 4 & 1 5 & 6 5 & 8 6 & 7 New diagram: color 7 & 8
Vertical angles: (opposite & congruent) Foldable 1 3 2 4 4 3 1 2 5 6 8 7 5 7 6 8 New diagram: color
Corresponding angles: f d Corresponding angles: a b c
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If parallel lines are crossed by a transversal then corresponding angles are congruent *because lines are parallel* Not Corresponding: because lines are not parallel* 5 2 3 8 7 4 1 6 4 3 2 1 6 5 8 7
Foldable Interior angles: New diagram: Discuss the meaning of interior: color angles
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Foldable Exterior angles: New diagram: color exterior angles
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Foldable Adjacent Vertical
Subtract known angle (100 degrees) from 180 degrees to find its supplementary adjacent angle 80
80 and 100 form supplementary angle 80 100
Vertical angles are congruent 80 100 80
Corresponding angles from one of the parallel lines are all congruent to their corresponding angles on the second parallel line 80 100 100 80 100 80 80
Find missing variable (x + 12)0 660
Find missing variable 120 (x + 50)