Please help in this difficult math geometry quiz.

 From:  Elang
11167.34 
Hi All

I just found the video which very close to the quiz above, and how to solve it... only, it's done via Inventor using constraints like my friend sugested:

https://youtu.be/1xsWKAoXYk4?t=21

(it is in 0:21 through 1:08)

cheers!