Transcript 4-2 and 4-3

Geometry 4.2
Parallel Lines and Transversals
Geometry 4.3
Transversals and Corresponding Angles
Transversal
A line is a transversal if and only if it intersects
two or more lines, each at a different point.
Lines cut by a transversal may or may not be
parallel.
98 percent of what we do in Geometry with transversals
will involve parallel Lines
You will know they are parallel because they will tell you,
or they will draw an extra arrow on the lines
When a transversal intersects two lines, eight angles are
formed
1
2
3
4
5
6
7
8
These are called interior angles
3
4
5
6
These are called exterior Angles
1
2
7
8
Corresponding angles are angles in similar locations
1
2
3
4
5
6
7
8
Alternate interior Angles
3
4
5
6
Alternate exterior Angles
1
2
7
8
Consecutive interior Angles
3
4
5
6
Things to know:
If the lines are parallel then:
Corresponding Angles are
Congruent
Things to know:
If the lines are parallel then:
Alternate Interior Angles are
Congruent
Things to know:
If the lines are parallel then:
Alternate Exterior Angles are
Congruent
Things to know:
If the lines are parallel then:
Consecutive Interior Angles are
Supplementary
So instead of this picture...
1
2
23
41
15
26
27
We can redraw it like this...
81
4.2
4-38
4.3
4-28