3.5+Using+Properties+of+Parallel+Lines

3.5 Using Properties of Parallel Lines
This section will teach you how to find relationships between parallel lines. Recognizing these types of lines will enable you to find interconnections between angles and distances. Also this is the basis of many proofs in other geometric areas. Theorem 3.11- Dual Parallel If two lines are parallel to the same line, then they are parallel to each other.

Theorem 3.12- Dual Perpendicular In a plane, if two lines are perpendicular to the same line, then they are parallel to each other.

__Sample Problems__:

1. If //line d// is parallel to //line a// and //line a// is parallel to //line b//, what can you conclude and using which theorem? 2. If //line b// is parallel to //line c// and //line b// parallel is to //line a//, what can you you conclude and using which theorem? 3. If //line a// is perpendicular to //line c// and //line b// is perpendicular to //line c//, what can you conclude and using which theorem?

__Links- sample problems and tutorials__ Dual Perpendicular Notes: http://library.thinkquest.org/2647/geometry/angle/proof3.htm Dual Parallel Notes: http://www.cliffsnotes.com/study_guide/Testing-for-Parallel-Lines.topicArticleId-18851,articleId-18780.html
 * More Practice Problems: http://www.tutorvista.com/q/in-a-plane-two-lines-perpendicular-to-a-third-line-are/q28703_87248