I always wanted to know this. Even when I went to school they taught irrational square roots through calculator, and before then a table at the end of the Mead notebook. I always thought that the schools were “teaching us stupid” – not knowing how to use our heads.
That said, I hope anyone reading this will enjoy this tutorial as much as I did.
Why no teacher of mine would give me the 8-10 minutes to teach me this when I asked is beyond me. Their reaction to this was “why? It’s so old.”
I know this is completely useless but then again, so is most of high-school/university level math unless you become an actuary. You learn it because you want to, not because it will have any bearing on your mundane life.