Parallel & Perpendicular Lines Proof

I introduce 2 more theorems that can verify that 2 lines are parallel. Each of these two theorems are proven with 2 column proofs. EXAMPLES at 0:04 7:54 Find free review test, useful notes and more at http://www.mathplane.com/ If you'd like to make a donation to support my efforts look for the "Tip the Teacher" button on my channel's homepage    / profrobbob