CK-12 Foundation
Ck 12: Determination of Unknown Angles Using Law of Cosines
[Free Registration/Login may be required to access all resource tools.] This lesson covers using the Law of Cosines to find an angle in a triangle.
CK-12 Foundation
Ck 12: Determination of Unknown Triangle Measures Given Area
[Free Registration/Login may be required to access all resource tools.] Looks at triangle problems where you are given the area and must use trigonometry to find unknown sides or angles.
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.
Math Open Reference
Math Open Reference: Law of Cosines
Learn about the Law of Cosines with this resource which offers detailed explanations, examples, and an interactive. Links to related topics.
Cuemath
Cuemath: Cosine Law
A comprehensive guide for learning all about the law of cosine with definitions, what is the law, and solved examples.
Math Open Reference
Math Open Reference: Law of Sines
A complete reference guide to the Law of Sines. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
CK-12 Foundation
Ck 12: Interactive Geometry: 7.7 Law of Cosines
Learn how the Law of Cosines uses the measure of angle C to provide an equation that relates the three sides of the triangle with angle C.
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.
Windstream
Ojk's Precalculus Study Page: The Law of Sines
An introduction to solving acute and obtuse triangles by using the law of sines, including a derivation of the formula. Includes several pictures and examples.
Instituto Latinoamericano de la Comunicacion Educativa
Red Escolar: Barcos en Alta Mar
In Spanish. Play submarine by using trigonometry, learn the law of sines and cosine, build an instrument to measure angles and distance and find out who was the father of Trigonometry.
Cut the Knot
Cut the Knot!: The Law of Cosines (Cosine Rule)
This site from Cut The Knot provides an overview of the law of cosines, complete with an explanation of the law and a proof of the law.
Other
Radford University: Law of Sines
This page states the Law of Sines and provides some interactive graphics that may help you understand the law more clearly.
ClassFlow
Class Flow: The Law of Cosines
[Free Registration/Login Required] This flipchart defines and uses the law of cosines to find the missing sides and angles of oblique triangles.
Interactive Mathematics
Interactive Mathematics: The Right Triangle and Applications
Learn how to "solve" a right triangle and apply the concept to real world situations using angles of elevation and depression.
Oswego City School District
Regents Exam Prep Center: Working on a Rescue Team Lab
Your pupils are part of the Yellowstone National Park rescue team which has just been dispatched to help located a downed plane. How can they effectively use the Law of Sines and the Law of Cosines to assist them in finding the plane?...
Calculator Soup
Calculator Soup: Law of Sines Calculator
Use the law of sines to calculate unknown angles or sides of a triangle. In order to calculate the unknown values, you must enter 3 known values.
Calculator Soup
Calculator Soup: Law of Cosines Calculator
Use the law of cosines to calculate unknown angles or sides of a triangle. In order to calculate the unknown values, you must enter 3 known values.
Calculator Soup
Calculator Soup: Triangle Theorems Calculator
Each calculation option has sub-bullets that list the sequence of methods used in this calculator to solve for unknown angle and side values including Sum of Angles in a Triangle, Law of Sines, and Law of Cosines.