Transcript Chapter 3.2 Notes: Use Parallel Lines and Transversals

Chapter 3.2 Notes: Use Parallel
Lines and Transversals
Goal: You will use angles formed by parallel
lines and transversals.
• Postulate 15 Corresponding Angles Postulate:
If two parallel lines are cut by a transversal, then the
pairs of corresponding angles are congruent.
Ex.1: The measure of three of the numbered angles is
120o. Identify the angles. Explain your reasoning.
• Theorem 3.1 Alternate Interior Angles Theorem:
If two parallel lines are cut by a transversal, then the
pairs of alternate interior angles are congruent.
• Theorem 3.2 Alternate Exterior Angles Theorem:
If two parallel lines are cut by a transversal, then the
pairs of alternate exterior angles are congruent.
• Theorem 3.3 Consecutive Interior Angles Thm:
If two parallel lines are cut by a transversal, then the
pairs of consecutive interior angles are
supplementary.
Ex.2: Find the value of x.
Ex.3: Find the value of x.
Ex.4: Use the diagram below.
o
m
1

105
a. If
, find m4, m5 and m8. Tell
which postulate or theorem you used in each case.
b. If m3  68 and m8  (2 x  4) , what is the
value of x? Show your steps.
o
o
Ex.5: Find the value of x and y.
Ex.6: Find
m1 and m 2
Ex.7: Find the mGHI .
Ex.8: Find the value of x.