1. Properties of Parallel Lines During this lesson, you will discover properties of parallel lines. Mrs. McConaughy1

2. DEFINITION: Parallel Lines Two or more lines are parallel if and only if ______________________. Mrs. McConaughy2

3. Investigation: Properties of Parallel Lines  Complete the investigation as described on your guided notes sheet.  Do you notice a pattern between the measures of corresponding angles, alternate interior angles, or alternate exterior angles? Mrs. McConaughy3

4. Investigative Results: Use your investigations to state at least three conjectures. Conjecture: If two parallel lines are cut by a transversal, then the corresponding angles which are formed ____________________. Conversely, _________________________. Mrs. McConaughy4

5. Investigative Results: Conjecture: If two parallel lines are cut by a transversal, then the alternate interior angles which are formed _______________. Conversely, _________________________. Conjecture: If two parallel lines are cut by a transversal, then the alternate exterior angles which are formed _______________. Conversely, _________________________. Mrs. McConaughy5

6. Investigative Results: Conjecture: If two parallel lines are cut by a transversal, then the same-side interior angles which are formed _______________. Conversely, _________________________. Mrs. McConaughy6

7. 1 2 3 4 a 5 6 7 8 9 10 11 12 b 13 14 15 16 1. a. Using the figure above, name all angles which are congruent to angle 4, given a // b. _____ _____ _____ b. Using the figure above, name all angles which are congruent to angle 16, given c // d. _____ _____ _____ c. Using the figure above, name all angles which are congruent to angle 1, given a // b and c // d. _____ _____ _____ c d Mrs. McConaughy7

8. Basic Math Sample: a. m ∠ 1 = ______ REASON: ______________ b. m ∠ 2 = _____ REASON: ______________ Mrs. McConaughy8

9. Homework Assignment Discovering Properties of Parallel Lines WS 1, 2, 6, and 7. Textbook, pages 118-119: 1-7 all, 11-17 all, 23, 25. Mrs. McConaughy9