The document discusses parallel lines and transversals. It states that if two parallel lines are cut by a transversal, then the corresponding angles are congruent according to the Parallel Lines Postulate. It provides examples of different types of angles formed when parallel lines are cut by a transversal, including alternate interior angles, alternate exterior angles, and same-side interior angles. It also gives examples of problems finding missing angle measures using the properties of parallel lines cut by a transversal.

1. Ch3.4_ParallelLines.notebook September 30, 2011
Chapter 3.4
Parallel Lines
Transversal ­ a line that crosses 2 or more lines
Postulate 9
Parallel Lines Postulate
If two parallel lines are cut
by a transversal, then the
corresponding angles are congruent
(a.k.a. The "Big­Small" Rule)
1

2. Ch3.4_ParallelLines.notebook September 30, 2011
Which angles are equal to Angle A?
B
A
D
C
F
E
GH
Which angles are equal to Angle F?
A B
C D
E F
G H
2

3. Ch3.4_ParallelLines.notebook September 30, 2011
Interior vs. Exterior
Exte
r ior
Inter
ior
Exte
rior
Alternate Exterior
1 2 (equal angles)
3 4
5 6 Alternate Interior
7 8 (equal angles)
Same­side Interior
(complementary)
3

4. Ch3.4_ParallelLines.notebook September 30, 2011
Find the missing angle measures
1200 2
3 4
5 6
7 8
Find the missing angle measures
E
H
450 I J
A B
C K D
G F
4