We all know this formula. .

This is perhaps the only piece of knowledge from school geometry that stays with a person for their entire life, even if they work as a barista or a copywriter.

But have you ever asked yourself the question: why squares specifically?
Why not cubes? Why not just the sum of the absolute values ?

If you ask a teacher, they will draw little squares on the sides of the triangle. If you ask a university professor, they will write down the definition of a scalar product.
And both of them, in essence, will deceive you. Or, to put it more mildly, they won't tell you the whole truth.

Today, we will unpack this 'black box' and see that the Pythagorean theorem is not about triangles at all. And it should be proven in a completely different way than we were taught.

The school curriculum doesn't provide an answer. Moreover, the history of teaching the Pythagorean theorem is a story of how living, visual geometry was turned into dry, dead algebra. We were led further and further away from understanding the essence and towards abstraction.

Today, we will analyze this path of degradation and show a proof that will bring you back to reality. Spoiler: the Pythagorean theorem is not about triangles. It's about mirrors.

Get ready to have all your preconceptions shattered!

The Pythagorean Theorem: The Great Deception of the School Curriculum. How Abstraction Killed Meaning