Honors Geometry: Section 3.3 part 2
Parallel Lines
Two lines are parallel iff they are
coplanar and do not intersect.
To indicate that AB is parallel to CD
AB // CD
we write _______
Arrowheads are use to
indicate parallel lines
in a figure.
Noncoplanar lines which do not
intersect are called skew.
Postulate 3.3.2
Corresponding Angles Postulate
(CAP)
If two parallel lines are cut by a
transversal, then corresponding
angles are congruent.
Theorem 3.3.3
Alternate Interior Angles Theorem
(AIAT)
If two parallel lines are cut by a
transversal, then alternate interior
angles are congruent.
1)
)
1) Given
Theorem 3.3.4
Alternate Exterior Angles Theorem
(AEAT)
If two parallel lines are cut by a
transversal, then alternate exterior
angles are congruent.
Theorem 3.3.5
Same-Side Interior Angles Theorem
(SSIAT)
If two parallel lines are cut by a
transversal, then same-side interior
angles are supplementary.
1.
1. Given
) m3  m5  180 )
)
)
Def. of Supp.
Examples: Find the value of the variable in each
problem.
3 x  5  7 x  11
16  4 x
4x
Examples: Find the value of the variable in each
problem.
3 y  5  7 y  11  180
10 y  6  180
10 y  186
y  18.6
Examples: Find the value of the variable in each
problem.
5w  8  3w  6  180
8w  14  180
8w  166
w  20.75