Today, I spent time allowing all of the students use the protractor and try to discover the parallel proof for the angle sum property. None of the students arrived at the proof, and all of them tried. I am not sure if I took the best approach on this. I believe there is some scaffolding to get the students to arrive at line of logic for a proof. I will be continuing the proof on Tuesday with a scaffold of all students trying to find the congruent angles and review the definitions to get to a place where they can possibly see a path to a solution. I am reluctant to hand the proof to them, but will probably scaffold to the position. I do like the productive struggle.