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 des