Law of Cosines
What it is, When to use it, and How to use it!
Formula:
where a and b are the given sides
C is the included angle
c is the unknown third side
When do you use it?
When you know two sides and an angle, it also works on any triangle.
Examples:
side a: 23.6
side b: 8.2
side c: unknown
angle c: 60 degrees
Try it!
side a: 11.1
side b: 15.3
side c: unknown
angle c: 15