1. Lesson 3.1 Identify Pairs of Lines and Angles

2. Definitions Parallel Lines- They don’t intersect and are COPLANAR Perpendicular Lines- They intersect at 90 degrees and are COPLANAR Skew Lines- They don’t intersect and are NOT COPLANAR Parallel Planes- Planes that don’t intersect

3. Postulate 13 Parallel Postulate There is exactly one line through point P and parallel to line k.. P k

4. Postulate 14 Perpendicular Postulate There is exactly one line through point P perpendicular to line k. P. k

5. Key Concept Corresponding Angles- Same side of transversal; one interior; one exterior & can’t be adjacent. 1 & 5, 3 &7, 2&6, 4&8 Consecutive Interior Angles- Same side of transversal; both interior. 3&5, 4&6 Alternate Interior Angles- Alternate transversal; both interior. 3&6, 4&5 Alternate Exterior Angles- Alternate transversal; both exterior. 1&8, 2&7 21 56 78 3 4 k m n * Line k is a transversal b/c it intersects two other lines