It's simply a matter of how you label them (yes the usual is a**2 + b**2 = c**2, but they're variables so the names don't really matter). Anyways, that kind of goes to the point of the picture not being very discernible in it's current state.

With your side notation you only need two cases A & B or A & C. Traditionally in such cases one uses switches, see Getopt::Std (among others).

PS> I didn't say there was no point in knowing what a hypotenuse was. I just joked that it's not something one is often called upon to find. --
perl -pe "s/\b;([mnst])/'\1/mg"