So that geometry question at the end of the first half of the friendship games competition had me intrigued. Also I wanted to defend my waifu’s honor even though she won I wanted to try to prove she was indeed correct. It’s what Twily would want. :3
 
I attempted to solve it but it seems I’m stuck as to how to proceed further. Analyzing all the different pics of the chalkboard through the movie I found it was hard to determine where the 10 degree angle is but by logic I figured that it was the angle at the bottom left corner.
 
I may have forgotten some of my geometry rules and postulates hehe anyone know how to finish this (it’s be quite awhile since high school geometry :p ). I got two equations two unknowns but no dice since the variables cancel each other.