Curated OER
Law of Cosines Practice
Pupils practice solving problems with non-right triangles. For this precalculus lesson, students define and identify the properties of the Law of Cosine. They solve problems and investigate the history behind Cosine.
Curated OER
Some More Trigonometry
Students define the law of cosine and its correct usage. In this trigonometry activity, students define the law of Heron's area formula and use it to solve problems. They review other trigonometric values and identify the identities.
Curated OER
Law of Cosines Word Problem
Learners solve problems using the law of cosines. In this precalculus lesson, students meet different criteria as they solve problems. They apply the formula for cosines to solve word problems.
Curated OER
The Laws of Sines and Cosines Made Simple!
Students explore the concept of law of sines and cosines. In this law of sines and cosines lesson, students construct a triangle tool from card stock and markers. Students use their triangle tool to aid in solving problems involving...
Curated OER
Algebra And Trigonometry - Week 3: Law of Sines
In this law of sines worksheet, pupils read story problems. They use both algebra and the law of sines and cosines to solve problems. This two page worksheet contains seven problems.
Curated OER
Trigonometry Involving Figures - Week 11
In this trigonometry worksheet, pupils use trigonometric functions to determine the measurement of angles and the length of sides in given figures. Most figures are comprised of rectangles containing parallel and perpendicular lines, as...
Curated OER
Journey of the Nez Perce
Young scholars study the retreat of the Nez Perce Native Americans into Montana while tracing their journey on a map. They use the law of cosines to solve problems based on the navigational methods of the Nez Perce. They work with both...
Curated OER
River Width
Students determine the level of accuracy needed for computations involving measurements and irrational numbers. They use the correct number of digits in computation to achieve an appropriate unit or level of accuracy when solving...
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...
Wolfram Research
Wolfram Math World: Heron's Formula
This site provides a detailed overview of Heron's Formula. Content includes a definition, example, and formula.
Other
Trigonometry: A Crash Review
This site really is a crash review on trigonometry! Formulas, functions - you name it, it's covered! Also includes self quizzes for practice.
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.
Oswego City School District
Regents Exam Prep Center: Law of Sines and Law of Cosines
This tutorial examines the law of sines and the law of cosines. Includes class notes, examples, and a variety of practice problems with solutions. The teacher resource consists of a lab that utilizes the law of sines and the law of cosines.
Wolfram Research
Wolfram Math World: Law of Cosines
This page from MathWorld.com gives a good explanation of the Law of Cosines, which relates the lengths of the legs of a triangle to the angles. This site shows how the formula is derived, along with a triangle to clarify variables. Also...
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...
Texas Instruments
Texas Instruments: Numb3 Rs: To Pythagoras and Beyond
Based off of the hit television show NUMB3RS, this lesson has students discover the Pythagorean relationships of different triangle types. By the end of the lesson, students should be able to take three given side lengths and compute...
Texas Instruments
Texas Instruments: Numb3 Rs: Where's Cheetah?
Based off of the hit television show NUMB3RS, this lesson has students set up a search region for a yacht that sank into the ocean. Using cylindrical coordinates and a little trigonometry, students are able to block off a certain portion...
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.
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.
Other
Dans Math: Lessons: Trigonometry
College professor Dan Bach reviews basic trig concepts, including trig functions, right triangles, circles, radians, and polar coordinates. Site includes animated graphs and detailed examples.
Math Planet
Math Planet: Algebra 2: Cosines
Defines and explores the law of cosines through examples and a video lesson. [1:41]
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.
CK-12 Foundation
Ck 12: Determination of Unknown Angles Using Law of Cosines
[Free Registration/Login may be required to access all resource tools.] Find an unknown angle of a side side side triangle using the Law of Cosines.
Varsity Tutors
Varsity Tutors: Hotmath: Graphing Calculator Practice: Right Triangles and Trigonometry
Practice using your graphing calculator for solving right triangle trigonometry and non-right triangle trigonometry. If you get stumped or if you would like to check your work, then select the View Solution button, which is located...