Let's face it: Geometric Proofs are very difficult for students, and they're very difficult for teachers to teach, because there is so much information required to get across (such as knowing that the idea that 3 = 3 is the "reflexive property of equality.")
To get my Geometry students started, I try to have them work first with algebraic proofs, of which they are much more confident, as they already know the basic steps (add 3 to both sides, divide both sides by 6, etc.)
This worksheet is designed to "hold their hands" through the process of proofs with them, while you circulate around the room to make sure they're getting it. I like to use groups of 4 so that they may help one another, and then call me over for help.
The preview file is a pdf so you may see exactly what you're getting; the product file is a word document, which you may edit to your liking.
DISCLAIMER: When students want to add three to both sides of an equation, I am admittedly sloppy in allowing them to write "+3" on both sides, and then writing the simplified equation underneath, and calling all of those steps "addition property of equality." Please feel free to modify the statements and reasons to fit what you feel is the most appropriate for your students.
Immediately before this worksheet, I use the worksheet named 'Constructions Day 1: Duplicate Segments, Duplicate Angles, Midpoints with key' (http://www.teacherspayteachers.com/Product/Constructions-Day-1-Duplicate-Segments-Duplicate-Angles-Midpoints-with-key-366694
), and immediately after this worksheet, I use the worksheet named 'Constructions Day 2 Fall 2013' (http://www.teacherspayteachers.com/Product/Constructions-Day-2-Fall-2013-1082528
Keywords: geometry, geometric proof, proof, proofs, introduction, Jonnard