The coolest fact in trigonometry that you learn way too late.... So I just spent the last 12 hours learning trig (occasional food breaks). I just want to share with you something really, really, really, really, awesome. Check this out, you're gonna be blown away The law of cosines, applied to a right triangle is c^2 = a^2+b^2 - 2abCosA Whereas A is equal to zero!!! So the law of cosines for a right triangle is, in fact, the Pythagorean theorm!!! Math is sooooooooo awesome. Why did it only take me the last quarter of the textbook to learn this fact???