Pythagorean Theorem Puzzle #1

I found three videos of visual proofs of the Pythagorean Theorem which I decided to use with my classes. I like these videos because they are strictly visual, no audio explanation. Once my students figure out how the proofs work, they have to explain them either in writing or on video. I created this and two other puzzles to go along with these videos. The video for this puzzle can be found at https://youtu.be/10rSltql2Vg.