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Activity
Math Is Fun

Math Is Fun: Triangle Identities

For Students 9th - 10th Standards
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.
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Activity
Math Is Fun

Math Is Fun: Solving Triangles

For Students 9th - 10th Standards
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,...
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Unknown Type
Khan Academy

Khan Academy: General Triangle Word Problems

For Students 9th - 10th Standards
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.
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Unknown Type
Khan Academy

Khan Academy: Solve Triangles Using the Law of Cosines

For Students 9th - 10th Standards
Solve missing triangle measures using the law of cosines. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
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Activity
Varsity Tutors

Varsity Tutors: Hotmath: Practice Problems: Law of Sines and Law of Cosines

For Students 9th - 10th Standards
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"...
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Unit Plan
CK-12 Foundation

Ck 12: Trigonometry: Sides of an Oblique Triangle

For Students 10th - 12th Standards
[Free Registration/Login may be required to access all resource tools.] Find the side of an oblique triangle using the Law of Cosines.
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Unit Plan
CK-12 Foundation

Ck 12: Trigonometry: Sides of an Oblique Triangle

For Students 10th - 12th Standards
[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.
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Handout
Math Is Fun

Math Is Fun: The Law of Cosines

For Students 9th - 10th Standards
Students learn about the law of cosines. The tutorial consists of a definition, examples, and practice problems to check for comprehension.
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Activity
Analyze Math

Analyze Math: Cosine Law Problems

For Students 9th - 10th Standards
Here are four problems to solve using the Law of Cosines. Two are SSS problems; two are SAS problems. Two have detailed solutions; two have answers given only. Notice the link at the bottom that takes you to a Law of Cosines calculator -...
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Activity
Analyze Math

Analyze Math: Triangle Problems

For Students 9th - 10th Standards
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.
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Unit Plan
Lawrence Hall of Science

The Math Page: Trigonometry: The Law of Cosines

For Students 9th - 10th Standards
Here is a site that clearly and thoroughly explains the law of cosines and how to use it. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who...
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Activity
Lawrence Hall of Science

The Math Page: Trigonometry

For Students 9th - 10th Standards
Concepts in Trigonometry are explained and illustrated here by a member of the math department at Borough of Manhattan Community College.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Mg Satellite

For Teachers 9th - 10th Standards
This task models a satellite orbiting the Earth in communication with two control stations located miles apart on Earth's surface. Students determine distances between various locations and, given a rate of travel, they determine the...
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Handout
Analyze Math

Analyze Math: Free Math Tutorials: Triangles

For Students 9th - 10th Standards
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.
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Unit Plan
CK-12 Foundation

Ck 12: Trigonometry: Law of Cosines

For Students 10th - 12th Standards
[Free Registration/Login may be required to access all resource tools.] Use Law of Cosines and Law of Sines in different triangle situations.
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Laws of Sines and Cosines

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] This concept teaches students to find missing sides and angles in non-right triangles using the Laws of Sines and Cosines.
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Unit Plan
CK-12 Foundation

Ck 12: Determination of Unknown Angles Using Law of Cosines

For Students 10th - 12th Standards
[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.
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Unit Plan
CK-12 Foundation

Ck 12: Determination of Unknown Triangle Measures Given Area

For Students 10th - 12th Standards
[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.
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Unit Plan
CK-12 Foundation

Ck 12: Trigonometry: General Solutions of Triangles

For Students 10th - 12th Standards
[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.
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Lesson Plan
Alabama Learning Exchange

Alex: Land Surveying Project

For Teachers 9th - 10th
This project resulted from of the collaboration of a computer aided drafting teacher, Chris Bond, and a math teacher, Lee Cable, (Hewitt-Trussville High School) to provide higher math expectations in CT and real life application in...
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Handout
Math Open Reference

Math Open Reference: Law of Cosines

For Students 9th - 10th Standards
Learn about the Law of Cosines with this resource which offers detailed explanations, examples, and an interactive. Links to related topics.
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eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 7.7 Law of Cosines

For Students 9th - 10th Standards
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.
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Activity
Georgia State University

Georgia State University: Hyper Physics: Law of Cosines

For Students 9th - 10th Standards
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.
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Graphic
Instituto Latinoamericano de la Comunicacion Educativa

Red Escolar: Barcos en Alta Mar

For Students 9th - 10th Standards
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.