Download Parallel Lines & Transversals

Parallel Lines
{
& Transversals
Lessons 3.3
Angles formed by
Transversals
You will learn to…
* identify angles formed by
transversals
transversal – a line that
intersects two or more coplanar
lines at different points
no
transversal
corresponding angles
1 2
3 4
6
7
5
8
Occupy corresponding positions
alternate interior angles
Lie between two lines
on opposite sides
alternate exterior angles
1 2
4
3
6 5
7 8
Lie outside two lines
on opposite sides of transversal
same-side interior angles
1 2
3 4
6 5
7 8
Lie between two lines
on same side of transversal
A line, ray, or segment that intersects 2 or more
COPLANAR lines, rays, or segments.
Parallel
lines
Transversal
transversal
Non-Parallel
lines
transversal
INTERIOR
–The space INSIDE the 2 lines
interior
EXTERIOR
-The space OUTSIDE the 2 lines
exterior
exterior
Interior Angles
1
3 4
5 6
7 8
2
<3 & <6 are Alternate Interior angles
<4 & <5 are Alternate Interior angles
<3 & <5 are Same Side Interior angles
<4 & <6 are Same Side Interior angles
Special Angle
Exterior Angles
<1 & <8 are Alternate Exterior angles
<2 & <7 are Alternate Exterior angles
Relationships
<1 & <7 are Same Side Exterior angles
<2 & <8 are Same Side Exterior angles
Special Angle Relationships
WHEN THE LINES ARE
PARALLEL
1
3
5
2
4
6
7 8
If the lines are not
parallel, these angle
relationships DO
NOT EXIST.
♥Alternate Interior Angles
are CONGRUENT
♥Alternate Exterior Angles are
CONGRUENT
♥Same Side Interior Angles are
SUPPLEMENTARY
♥Same Side Exterior Angles are
SUPPLEMENTARY
120°1
60°3
120° 5
7
60°
2 60°
4 120°
6 60°
8 120°
Let’s Practice
m<1=120°
Find all the remaining
angle measures.
40°
120°
Find all the
missing angle
measures, and
name the
postulate or
theorem that
gives us
permission to
make our
statements.
Another practice problem
Assignmen
t
Pg 160, 13-33
3.3 A & B