Download 3 ∠ and 6 ∠ 8 ∠ 3 ∠ and 5 ∠ 8 ∠ 7 ∠

Section 3.4 – Parallel Lines and Transversals
Informal Geometry
Name: _____________________________
Period: __________
Goal: Be able to find the congruent angles formed when a transversal cuts parallel lines.
Warm up:
Directions: Use the diagram below to describe the relationship between the pairs of angles.
1.)
3 and 6
2.)
1 and 8
3.)
3 and 5
4.)
4 and 8
5.)
1 and 7
Properties of Parallel Lines
Corresponding Angles Postulate
If a transversal intersects two parallel lines, then
_________________________________________________.
Alternate Interior Angle Theorem
If a transversal intersects two parallel lines, then
_________________________________________________.
Alternate Exterior Angles Theorem
If a transversal intersects two parallel lines, then
_________________________________________________.
Same-Side Interior Angles Theorem
If a transversal intersects two parallel lines, then
_________________________________________________.
Same-Side Exterior Angles Theorem
If a transversal intersects two parallel lines, then
_________________________________________________.
Example 1: l  m
Find m1 and m2 .
Example 2: Find the measure of the numbered angle.
a.)
b.)
c.)
2
1
3
75°
60°
150°
Example 4: Find the value of x.
Example 5: Find the value of x.
(8x – 1)°
85°