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.

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

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

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

Video Parallel Lines & Transversals Video Or go to the following site by copying and pasting into your browser. https://www.khanacademy.org/math/geometry/parallel-and-perpendicular-lines/ang_intro/v/angles-formed-by-parallel-lines-and-transversals

Examples Identify each pair of angles as 2 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

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