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Section 3.1 – Geometry
Geometry
Name: _____________________________
Period: __________
Goal: Be able to identify angles formed by two lines and a transversal. Prove and use properties of
parallel lines.
Directions: State what these words mean to you in your own words.
Exterior:
Interior:
Alternate:
Corresponding:
Transversal – a _________ that ____________ two coplanar lines at ___________ distinct points.
(Example: line t)
Directions: Name pairs of angles formed by lines and.
Alternate Exterior Angles:
m
Alternate Interior Angles:
Same-side Interior Angles:
Same-side Exterior Angles:
Corresponding Angles:
l
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: Given: a  b
Prove: m2  m3  180
Statements
Example 2: l  m
Find m1 and m2 .
Example 3: Find m1 .
Reasons
Example 4: Find x .
Example 5: Find m1 and m2 . Justify each answer.
a.
b.
Example 6: Find x and y. Then find the measure of the angles.