It'd be nice if it drew the triangle out for you. I wrote virtually the same program, except it was a set of individual ones, for my TI-83+. It'd be a giant pain in the ass to write a program on a calculator with the functionality of input fields like that, but the calculation is incredibly simple to do.
Except my calculator's RAM has been cleared like 5 times since I wrote them. They made my precalc tests a lot easier when we were doing that sort of stuff.
Razzle them. Dazzle them. Razzle dazzle them.