Khan Academy
Khan Academy: Solve for an Angle in Right Triangles
Given two sides in a right triangle, find one of the acute angles using trigonometry.
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.
Homeschool Math
Homeschool Math: Introduction to Sine
This is an introductory lesson about the trigonometric function sine. Students will study several similar right triangles and the ratio of certain two sides in them.
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.
Wolfram Research
Wolfram Math World: Trigonometry
This site provides a good definition of trigonometry. Includes many links to key terms and many more to related terms. This site may be used as a refresher for students who have finished the course, or students currently studying the...
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.
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.
ClassFlow
Class Flow: Trigonometry
[Free Registration/Login Required] Students explore trigonometric functions using the interactive features of Activstudio. Students apply their understanding of trigonometric sense to determine the side lengths and angles of various...
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Trigonometric Ratios
Find a quick, concise explanation of the trigonometric ratios: sine, cosine and tangent. Examples are given and clearly explained.
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.
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.