In a previous blog post about proofs in algebra, I wrote about how to a geometric style proof to solving an algebraic equation. The video embedded into this post models how to justify the solving of an equation with a two-column proof and the justifying of two problems involving the segment addition postulate and the angle addition postulate. Introducing proofs with algebra makes sense. You build upon your knowledge of solving equations to learn the new skill of creating proofs.

To be able to write proofs effectively, you must know definitions, postulate, properties and theorems. As always, I hope this information in the video and blog is helpful. Feel free to comment or ask a question.

Here is a video about the Segment Addition Postulate. I made the video in the fall of 2009. I was still really new to making math videos at the time. I have been making more videos this year. Well, I have been blogging about math more this year. Once I get to this topic again, I will be sure to create some images and write a good post.