1. Geometry Agenda 1. ENTRANCE 2. go over practice
Proving Lines Parallel
4. Practice Assignment
5. EXIT

2. Practice

3. Transitive Property If a=b and b=c, then a=c.
If and , then
If 12 and 23, then 13.

4. Example #7
Given: a||b
Prove: 13
1. a||b
2. 14
3. 43
4. 13

5. Example #8 Given: a||b Prove: 1 supple 2 1. a||b 2. m2+m3=180
3. 31
4. m2+m1=180
5. 1 supple 2

6. 3-2 Proving ________ Parallel
Chapter 3
3-2 Proving ________ Parallel

7. Flowchart Proof Proof with statements in boxes and reasons below them.
ex: Given: 2x – 7 = 3
Prove: x = 5

8. Postulate 3-2, Theorems 3-3 and 3-4
If two lines and a transversal form:
Corresponding angles that are congruent
Alternate interior angles that are congruent
Same-side interior angles that are supplementary
then the two lines are __________.

9. Theorem 3-5
If two lines are parallel to the same line, then they are parallel to each other.
x||y and y||z
therefore, x||z

10. Theorem 3-6
In a plane, if two lines are ___________ to the same line, then they are parallel to each other.
gh and hj
therefore, g||j

11. Example #1 Which lines (if any) must be parallel if: a. 26
c. 10 supple 11
d. 38

12. Example #2
Find x for which m||n.

13. Example #3
Find x for which a||b.

14. Example #4
Find x for which p||q.

15. Example #5
Given: 32
Prove: m||n

16. Example #6
Given: at
bt
Prove: a||b
(prove Thm 3-6)

17. Practice
WB 3-2 # 2-13
EXIT