PowerPoint presentations covering seven sessions on parallel and perpendicular lines problems. I use them to present a topic to my class and give them a few examples and/or sample problems. Topics include 1. Parallel and perpendicular postulate 2. Perpendicular lines 3. Parallel lines and transversals 4. Proving lines parallel 5. Proofs involving parallel lines 6. Parallel lines in a coordinate plan 7. Perpendicular lines in a coordinate plane. The slides are full of powerpoint animation and can be edited to fit your needs.