Just wondering if I proved the congruency part right and how do I answer the second part? Still confused over previous post. Is the arc 45 degrees? Took forever to get this to upload!

Theorem 2 says that if two chords are parallel, then the arcs between them are congruent. Arcs AE and BF are between the parallel chords AB and EF so this makes arcs AE and BF congruent. It says that the arcs between EF and CD are congruent. This makes arcs EC and FD congruent so the total arcs of AC and BD are congruent. Since all lines are parallel and all other arcs are congruent then the arcs between AB and CD are congruent.