1. 3-1 Parallel Lines & Transversals
Parallel Lines: Coplanar lines that do not intersect.
Symbol: || means “is parallel to”
Parallel Planes: Planes that do not intersect, for example floors and ceilings of a house.

2. Geometry Lab
The figure below is a rectangular prism. Name the following parts of the figure.
All parallel planes.
All planes that intersect plane ABC and name their intersections.
Identify all segments parallel to BF. A C D B H G F E

3. Skew Lines
Skew lines: Lines that do not intersect and are not coplanar.
Segments and rays contained in skew lines are also skew.
AE and GF are skew segments. A C D B H G F E

4. Transversal
Transversal: In a plane, a line is a transversal if and only if it intersects two or more lines at a different point.
Exterior angles: 1, 2, 7, 8
Interior angles: 3, 4, 5, 6
Consecutive interior angles: 3 with 5, 4 with 6
Alternate exterior angles: 1 with 8, 2 with 7
Alternate interior angles: 3 with 6, 4 with 5
Corresponding angles: 1 with 5, 2 with 6, 3 with 7, 4 with 8 2 1 7 8 6 5 3 4

5. Video Parallel Lines & Transversals Video
Or go to the following site by copying and pasting into your browser.

6. Examples Identify each pair of angles as2 1 7 8 6 5 3 4
Identify each pair of angles as
alternate interior, alternate exterior, consecutive interior, corresponding, or vertical
1. 3 and 5
2. 1 and 8
3. 1 and 4
4. 4 and 5
5. 3 and 7
Consecutive interior
Alternate exterior
Vertical
Alternate interior
Corresponding

7. Your Turn
Try #1-10 on page 144
Check your answers with your neighbor when you both finish.
Begin homework #18 on new assignment page