[b]Strategy[/b][br]You observed the given diagram, then made a conjecture. Then you built a model and gathered some data. That may have caused you to rethink your conjecture somewhat--or perhaps it strengthened your conviction. Either way, by this phase you should have a conjecture that you truly believe in. The goal now is to demonstrate or [i]prove[/i] your conjecture.[br][br]Does measuring angles prove whether or not angles are congruent? What does?[br][br]You can use any geometric tools, working on paper and/or in geogebra to try and find a way of demonstrating your conjecture.[br][br][b]Two-Column Proof[br][/b]Now you've developed a way to demonstrate that your conjecture is true. A proof is how you clearly present your solution.[br][br]It begins with the problem as it is [i]given[/i] to you. From there, you take one logical step at a time towards the conclusion you want to show is true. In this case, the conclusion you want to prove true is your conjecture.[br][br]Complete the proof in two-column form.