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.
Government of Alberta
Learn Alberta: Math Interactives: Exploring Trig Ratios
Investigate the cosine, sine, and tangent ratios of trigonometry using this interactive Learn Alberta math resource. Students will use these ratios to determine a right triangle's unknown side or angle. Be sure to follow the link to the...
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.
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Law of Sines and Law of Cosines
Sixteen problems present practice working with the Law of Sines and Law of Cosines. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click the "View Solution"...
Khan Academy
Khan Academy: Laws of Sines and Cosines Review
Review the law of sines and the law of cosines, and use them to solve problems with any triangle.
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.
Analyze Math
Analyze Math: Free Math Tutorials: Triangles
The geometry tutorial investigates the definitions and properties of triangles. Topics included are isosceles, equilateral, and right triangles. In addition, the sine and cosine laws of triangles are defined.
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.
Oswego City School District
Regents Exam Prep Center: Working on a Rescue Team Lab
Your students 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?...
Georgia State University
Georgia State University: Hyper Physics: Laws of Sines and Cosines
At the bottom of this page from the Georgia State University, you will two real-world applications of the Laws of Sines and Cosines (in the context of velocity vectors.)
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.
McGraw Hill
Glencoe Mathematics: Online Study Tools: Self Check Quiz on Law of Cosines
The online assessment demonstrates knowledge of Algebra II. The questions test students on the law of cosines.
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,...
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.
Wolfram Research
Wolfram Math World: Acute Triangle
This MathWorld site gives a short discussion on acute triangles with links to related terms and topics. The site offers a discussion on the least number of acute triangles to compose various polygons, and a discussion on the relationship...
Khan Academy
Khan Academy: General Triangle Word Problems
Solve word problems that involve general triangles using trigonometry. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Other
Karl's Calculus Tutor: Trigonometric Functions
Great application of trig and introduction to the trig functions. Also found here are the Law of Sines and Law of Cosines as well as other trig topics to review.
Analyze Math
Analyze Math: Triangle Problems
Here are five triangle problems to solve using the Law of Sines, Law of Cosines, Pythagorean Theorem, and trigonometry. All problems have detailed written solutions included.
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.
Windstream
Ojk's Precalculus Study Page: The Law of Cosines
An introduction to solving acute and obtuse triangles by using the law of cosines, including a derivation of the formula. Includes several pistures and examples.
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: Sides of an Oblique Triangle
[Free Registration/Login may be required to access all resource tools.] This lesson covers using the Law of Cosines to find the third side of a triangle.
CK-12 Foundation
Ck 12: Trigonometry: Sides of an Oblique Triangle
[Free Registration/Login may be required to access all resource tools.] Find the side of an oblique triangle using the Law of Cosines.
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.