Open Middle Challenge: Parallel Lines and Related Angles
Your task:

Without repeating digits, change the input boxes on the left try to make lines a and b parallel and the rest of the diagram true. The picture on the right IS drawn to scale. LARGE POINTS are also moveable.
Where would it not be ideal to put a 0? Why is this?
Where would it not be ideal to place a 5? Why is this?
What other frustrations or roadblocks did you run into while attempting the problem above? Explain.