College? Pythagorean Theorem is mid-level high school math.
I did once talk to a high school math teacher about a graphics program I was hacking away on at the time, and she was surprised that I actually use the stuff she teaches. Which is to say that I wouldn't expect most programmers to know it exactly off the top of their head, but I would expect they've been exposed to it and can look it up if needed. I happen to have it pretty well ingrained in my brain.