Other
Trig Without Tears: Solving Triangles
This page provides a good explanation of how to solve oblique triangles (triangles containing no right angles.) The Law of Cosines section is about halfway of the way down the page.
Math Is Fun
Math Is Fun: Solving Triangles
Find guidelines to help you "solve" triangles, which means finding the value of missing sides and angles. Provided are examples of six scenarios in which you can solve a triangle's missing measurements, as well as relevant equations,...
Math Is Fun
Math Is Fun: Triangle Identities
View examples of triangle identities, equations that are true for all triangles: Law of Sines, Law of Cosines, and Law of Tangents. Follow links to learn more about the purpose and examples of each identity.
CK-12 Foundation
Ck 12: Trigonometry: General Solutions of Triangles
[Free Registration/Login may be required to access all resource tools.] A summary of when to use the law of cosines or the law of sines to solve triangles.
Cuemath
Cuemath: Sine Law
This comprehensive guide explores the topic of sine law, by finding answers to questions like what is the law of sines, what are the applications of sine law, and proof of the sine law. Includes solved examples and practice questions.
BBC
Bbc: Gcse Bitesize: Sine and Cosine Rules
BBC provides a three part lesson on solving triangles, by using the sine rule and cosine rule.
Georgia State University
Georgia State University: Hyper Physics: Law of Cosines
This page from the Georgia State University provides a definition of the Law of Cosines. Also includes a "calculator" to help you find side lengths and opposite angles when you are given either three sides or two sides and a third angle.