They proved the Pythagorean Theorem using trigonometric methods.
Now it’s “cheating” to simply let a = c*cos(x) and
b = c*sin(x) and proving that a^2 + b^2 = c^2.
I’m a bit unclear at what point a trigonometric method isn’t cheating.
I think I recall seeing their proof and yes I was impressed but I’m not a theoretician.
It may not be pure, but they are kids. I would only hold criticism for those who have been mathematicians for years.