> Why didn't author reference any of the previous work? Doesn't seem like a serious article about math so much as a feel-good story. I mean, Wikipedia shows

> Why didn't author reference any of the previous work? Doesn't seem like a serious article about math so much as a feel-good story. I mean, Wikipedia shows a better proof in [this section titled "proof using similar triangles"](https://en.wikipedia.org/wiki/Pythagorean_theorem#Proof_using_similar_triangles https://en.wikipedia.org/wiki/Pythagorean_theorem#Proof_usin...), which kinda starts the same way, but it's a lot shorter and doesn't require the Law-of-Sines nor infinite-series. If anyone wants to design further "trigonometric" proofs, they can just start from what's on Wikipedia and add in steps that rely on trigonometry.