Two Teenagers Found a New Proof of the Pythagorean Theorem — Here’s How

An inspirational example of how elementary math is open to everyone

Keith McNulty

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Recently, two teenage girls — Calcea Johnson and Ne’Kiya Jackson — gave a presentation to the American Mathematical Society where they demonstrated a new proof of the Pythagorean Theorem. Their proof has caused quite a stir.

One reason for the stir delights me and makes me incredibly happy as a teacher of mathematics. By all accounts, these two girls are shaking up the majority white male math establishment. This is just an awesome turn of events and one which should inspire anyone — no matter what their background — that excellence in your chosen field of study is always attainable if you have enough joy and passion for what you do.

Another reason for the stir is that the proof these young trailblazers have proposed might make a few established mathematicians eat their words.

This is because their proof uses trigonometry.

Now why is that such a big deal? Well, many of our trigonometric identities and laws depend on the Pythagorean Theorem, and so a number of mathematicians have suggested that any proof of the theorem using trigonometry is circular logic. Put another way, they argue that using trigonometry to prove Pythagoras is basically using A to prove B, when A already depends on B. One strong proponent of this point of view was the mathematician Elisha Loomis, who published

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Keith McNulty

Pure and Applied Mathematician. LinkedIn Top Voice in Tech. Expert and Author in Data Science and Statistics. Find me on LinkedIn, Twitter or keithmcnulty.org