Download Holt McDougal Geometry 3-2

3-2
Angles Formed by Parallel Lines
and Transversals
What you need…….
PHONES AWAY
Warm-Up Sheet
Pencil/Pen
Guided Notes Sheet from Yesterday
Notebook
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Warm-Up 10/18
Identify each of the following.
a. a pair of parallel segments
BF || EJ
b. a pair of skew segments
BF and DE are skew.
c. a pair of perpendicular segments
BF  FJ
d. a pair of parallel planes
plane FJH || plane BCD
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
• Task 1: On the bottom of the sheet from
yesterday under the table we completed
about Parallel lines, Parallel Planes and
Skew lines, complete the section that says
Examples!
• You will have 8 minutes to get as much
done as you can!
• When finished, just hang tight…
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Goal:
I can identify the types of
angles formed by two lines
and a transversal.
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Interior or Exterior? How do you know?
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Example 2: Classifying Pairs of Angles
Give an example of each angle pair.
A. corresponding angles
1 and 5
B. alternate interior angles
3 and 5
C. alternate exterior angles
1 and 7
D. same-side interior angles
3 and 6
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Work Time!.. You may listen to music
Work to complete the bottom portion of your
worksheet on the Transversal side. You will
have the rest of class to work on this and
WHAT YOU DON’T FINISH IS
HOMEWORK
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
What you need…….
PHONES AWAY
Warm-Up Sheet
Pencil/Pen
Notebook
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Warm-Up 10/19
Give an example of each angle pair from the
figure.
A. corresponding angles
1 and 3
B. alternate interior angles
2 and 7
C. alternate exterior angles
1 and 8
D. same-side interior angles
2 and 3
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Objective
Prove and use theorems about the
angles formed by parallel lines and a
transversal.
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
True or false…
If a transversal is perpendicular to
two parallel lines, all eight angles are
congruent.
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Exit Ticket
In order to leave today, you need to hand
me a piece of paper that answers the
following questions:
1. Do you feel like you met our goal for
today?
2. How do you know?
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
For class, you need…….
PHONES AWAY
Warm-Up Sheet
Pencil/Pen
Notebook
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Warm-Up 10/20
Given m∠6 = 142°,
find the measure of
each missing angle.
Give your reasoning.
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Objective
Prove and use theorems about the
angles formed by parallel lines and a
transversal.
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
If l ll m, find the value of the missing
variable.
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
If l ll m, find the value of the missing
variable.
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
If l ll m, find the value of the missing
variable.
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
If l ll m,
find the
measure
of each
missing
angle.
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
WORK TIME
You will be given a packet that
you need to work on today and
tomorrow in class. Whatever
you don’t finish after tomorrow
is homework, DUE TUESDAY
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Example 1: Using the Corresponding Angles
Postulate
Find each angle measure.
A. mECF
x = 70 Corr. s Post.
mECF = 70°
B. mDCE
5x = 4x + 22
x = 22
mDCE = 5x
= 5(22)
= 110°
Holt McDougal Geometry
Corr. s Post.
Subtract 4x from both sides.
Substitute 22 for x.
3-2
Angles Formed by Parallel Lines
and Transversals
Example 2: Finding Angle Measures
Find each angle measure.
A. mEDG
mEDG = 75° Alt. Ext. s Thm.
B. mBDG
x – 30° = 75° Alt. Ext. s Thm.
x = 105 Add 30 to both sides.
mBDG = 105°
Holt McDougal Geometry
3-2
Angles Formed by Parallel Lines
and Transversals
Check It Out! Example 2
Find mABD.
2x + 10° = 3x – 15° Alt. Int. s Thm.
x = 25
Subtract 2x and add 15 to
both sides.
mABD = 2(25) + 10 = 60° Substitute 25 for x.
Holt McDougal Geometry