Angles and Parallel Lines

2. Angles and Parallel Lines Section 3.2 Sol: G.3a, c, f E.Q.: Compare and contrast parallel lines with a transversal and non-parallel lines and a transversal.

3. Angles and Parallel Lines • If two parallel lines are cut by a transversal, then the following pairs of angles are congruent. • Corresponding angles • Alternate interior angles • Alternate exterior angles • If two parallel lines are cut by a transversal, then the following pairs of angles are supplementary. • Consecutive interior angles • Consecutive exterior angles Continued….. Lesson 2-4: Angles and Parallel Lines

4. 3-1 Corresponding angles postulate • If two parallel lines are cut by a transversal, then each pair of corresponding angles are congruent.  2  6, 1  5,3  7,4  8 1 2 3 4 5 6 7 8 Lesson 2-4: Angles and Parallel Lines

5. 3-2 Consecutive Interior Angles Theroem If two parallel lines are cut by a transversal, then each pair of consecutive interior angles is supplementary. m3 +m5 = 180º, m4 +m6 = 180º 1 2 3 4 5 6 7 8 Lesson 2-4: Angles and Parallel Lines

6. Alternate Angles • 3-1 Alternate Interior Angles Thereom: If two parallel lines are cut by a transversal, then each pair of alternate interior angles are Congruent. • 3-3 Alternate Exterior Angles: If two parallel lines are cut by a transversal, then each pair of alternate exterior angles are Congruent. 3  6,4  5 2  7,1  8 1 2 3 4 5 6 7 8 Lesson 2-4: Angles and Parallel Lines

7. 3-4 Perpendicular Transversal Thereom • In a plane, if a line is perpendicular to one or more parallel lines, then it is perpendicular to the other. Note: To show on a picture that two lines are parallel, we often will put arrows in the middles of the line, where the same number of arrows denotes parallelism.

8. Ex: l||m and a||b l m b a

13. Assignments Classwork: WB pg 63-64 1-12,14,15,16 Homework: Book Pg 153-154 5,7-9,12-20,22,23-24