You'll be spinning in unit circles once you read through this jumbo-sized resource of everything you need to know about trigonometry. Each page has color-coded examples with explicit directions that detail the problems and...

This page from MathWorld.com gives a good explanation of the Law of Cosines, which relates the lengths of the legs of a triangle to the angles. This site shows how the formula is derived, along with a triangle to clarify variables. Also...

At the bottom of this page from the Georgia State University, you will two real-world applications of the Laws of Sines and Cosines (in the context of velocity vectors.)