### Home > PC > Chapter 2 > Lesson 2.1.2 > Problem2-27

2-27.

Label all of the sides and angles first. Standard labeling is captial letters for angles.
The side opposite the angle is the lower case letter of the angle.

$a^2=b^2+c^2-2bc\cos{A}$

$\frac{a}{\sin A}=\frac{b}{\sin B}=\frac{c}{\sin C}$