In this lesson I will be teaching you about the properties of parallel and perpendicular lines. Just a word of warning there will be lots of theorems and postulates in the lesson so be ready to take good notes. In the lesson I will continue to build your knowledge of parallel lines and introduce you to perpendicular lines. You may know that perpendicular lines are those lines that are formed when two lines meet at right angles- i.e. the angle formed is 90 degrees. As I will show you in the lesson there are some pretty cool features about perpendicular lines that you need to know. I want to continue to stress that in geometry we do proofs and you will be expected to recall all previous theorems, postulates and properties. Now I don’t expect you to know them by memory but you should be able to quickly reference them in your notes. As such if your notes are not well organized, complete and neat I would recommend you take the time to rewrite them. Once you complete geometry you’re notes can become a wonderful reference for you to review for tests like the SAT/ACT – so be smart and invest in developing your note taking skills.