Parallel Lines and Transversals

1
Parallel Lines and Transversals

• Section 3-1

2

• 2 lines that do not intersect are either parallel
  or skew.
• Parallel lines ( lines) do not intersect and
  are coplanar.
• Skew lines do not intersect and are not coplanar.

3

• Parallel planes ( planes) do not intersect.
• Plane X is parallel to plane Y
• A line and a plane are parallel if they do not
  intersect.

G
H
X
plane Y
E
F
D
C
Y
A
B
4

• A transversal is a line that intersects 2 or more
  coplanar lines in different points.

transversal
exterior
1
2
3
4
interior
6
5
7
8
exterior
5

• Alternate interior angles are 2 nonadjacent
  interior angles on opposite sides of the
  transversal.

1
2
3
4
6
5
7
8
6

• Consecutive interior angles are 2 interior angles
  on the same side of the transversal.

1
2
3
4
6
5
7
8
7

• Alternate exterior angles are 2 nonadjacent
  exterior angles on opposite sides of the
  transversal.

1
2
3
4
6
5
7
8
8

• Consecutive exterior angles are 2 exterior angles
  on the same side of the transversal.

1
2
3
4
6
5
7
8
9

• Corresponding angles are 2 angles in
  corresponding positions relative to the 2 lines.

1
2
3
4
6
5
7
8
10
Joke Time

• What did E.T.s Mom say when he got home?
• Where on Earth have you been?

11

• What happened when the pig pen broke?
• The pigs had to use a pencil.