Warm Up:
l
Given:
m
m1 = 62°
1
2 m9 = 90°
43
9 10
12 11
5
8
1. Name the relationship
between 3 and 1.
2. m3 = ____
3. Name the relationship
between 9 and 10.
4. m10 = ____
6
7
n
3.1: Parallel Lines & Transversals
Objectives:
1. Identify the relationships of lines
2. Identify angles formed by transversals
Vocabulary:
Parallel, perpendicular, skew, transversal,
corresponding angles, alternate exterior angles,
alternate interior angles, consecutive interior
angles
3.1: Parallel Lines & Transversals
Vocabulary:
Parallel: extends indefinitely and never intersect
What can be parallel?
-parallel lines
Real Life Ex: Sides of the road
-parallel planes
Real Life Ex: Floor and Ceiling
3.1: Parallel Lines & Transversals
Vocabulary:
Perpendicular: two lines that intersect to form right
angles.
Real Life Ex: sides of the board
Transversal: a line that intersects two or more lines in
the same plane at different points.
Real Life Ex: railroad tracks crossing the road
Skew: Lines in different planes that do not intersect
Real Life Ex: road and tree
Which line is a transversal?
n
1 2
4 3
5 6
8 7
Angle Types:
Interior: 3, 4, 5, 6
Exterior: 1, 2, 7, 8
b
a
3.1: Parallel Lines & Transversals
Corresponding Angles: angles that occupy
corresponding positions. Same side of transversal,
one on the interior and one on the exterior.
1 22
44 33
55
88
66
77
Examples: <1 and < 5, <2 and <6, <3 and <7, <4 and <8
3.1: Parallel Lines & Transversals
Alternate Exterior Angles: angles on opposite sides
of the transversal that are both exterior
1 2
4 3
5 6
88 77
Examples: <1 and <7, <2 and <8
3.1: Parallel Lines & Transversals
Alternate Interior Angles: angles on opposite sides
of the transversal that are both interior
1 2
44 33
5 66
8 7
Examples: <3 and <5, <4 and <6
3.1: Parallel Lines & Transversals
Consecutive Interior Angles: angles on the same
side of the transversal, both interior
1 2
44 33
5 6
8 7
Examples: <3 and <6, <4 and <5
What is the relationship
between…..
a
b
• <1 and <9?
1
2
4
3
9 10
12 11
• <3 and <10?
• <2 and <12?
c
Find the transversal first!!
• <4 and <10?
Find:
a
corresponding angles
b
consecutive interior angles
1
2
4
3
9 10
12 11
alternate exterior angles
alternate interior angles
5
NEXT TRANSVERSAL!
6
8
7
c
Exit Slip:
a
Name a pair of…
b
1. corresponding angles
1
2
4
3
9 10
12 11
2. consecutive interior angles
3. alternate exterior angles
4. alternate interior angles
5
LAST TRANSVERSAL!
6
8
7
c
Geometry
Homework:
•
p.176-178 #21-30, 38-40, 55, 56