Is there something for OS X that can draw lines/angles

I need something to help with my math homework. I can’t figure out how to use Grapher to do this and I’ve been using Illustrator which is kind of a pain.

Basically I need something that lets me draw a line of a given length at a certain angle, then another line, then compare those lines, and complete triangles, and things like that.

Anyone have any experience with something like that?