How do you use theorems about triangles to solve problems?

Step-by-step explanation:

Triangles can be solved if you know either of three pieces of information:

Three sides Two sides and one angle Two angles and one side

You can solve for the remaining sides and angles using law of sine and law of cosine.

Law of sine:

(sin A) / a = (sin B) / b = (sin C) / c

Law of cosine:

c² = a² + b² - 2ab cos C

Here, A is the angle opposite side a, B is the angle opposite side b, and C is the angle opposite side c.

Law of cosine can also be written as:

b² = a² + c² - 2ac cos B

a² = b² + c² - 2bc cos A

And law of sine can also be written as:

a / (sin A) = b / (sin B) = c / (sin C)

(Notice that when C = 90°, law of cosine becomes Pythagorean theorem.)