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.
CK-12 Foundation
Ck 12: Trigonometry: Conversion Between Degrees and Radians
[Free Registration/Login may be required to access all resource tools.] Express a degree measurement in radians.
Clark University
Clark University: Dave's Short Trig Course: Trigonometric Functions
The Clark University site shows and explains the graphs of the six trigonometric functions. It explains how to find an arbitrary angle measurement using trig. Also, it explains that sine and cosine functions are complementary.
CK-12 Foundation
Ck 12: Trigonometry: Proofs of Trigonometric Identities
[Free Registration/Login may be required to access all resource tools.] This lesson uses trigonometric identities to prove other identities.
Mathigon
Mathigon: Geometry: Triangles and Trigonometry: Triangles Congruence
This lesson focuses on triangle congruence; it shows the ways to prove that triangles are congruent.
Lawrence Hall of Science
The Math Page: Trigonometry: Trigonometric Identities
This resource clearly and thoroughly explains the many types of trigonometric identities. There are example problems solved, problems for the student to attempt, and answers to the student problems.
Illustrative Mathematics
Illustrative Mathematics: F Tf Sum and Difference Angle Formulas
The goal of this task is to have students derive the addition and subtraction formulas for cosine and tangent, and the subtraction formula for cosine, from the sum formula for sine. Aligns with F-TF.C.9.
Mathigon
Mathigon: Geometry: Angles and Polygons: Drawing Triangles
This lesson focuses on the Triangle Inequality, when the sum of the lengths of any two sides of a triangle is greater than the length of the third. When this happens, the three sides cannot form a triangle.
Oswego City School District
Regents Exam Prep Center: Trigonometric Ratios
A collection of lessons and practice exercises on trigonometric ratios. Students will learn how to solve for an angle and for a side, and to apply trigonometry in setting up and solving word problems.
TeachEngineering
Teach Engineering: You've Got Triangles!
Students learn about trigonometry, geometry and measurements while participating in a hands-on interaction with LEGO MINDSTORMS NXT technology. First they review fundamental geometrical and trigonometric concepts. Then, they estimate the...
University of Saskatchewan (Canada)
University of Saskatchewan: Trigonometric Identities
The University of Saskatchewan provides an explanation of trigonometric identities, including the reciprocal identities, the addition and subtraction formulas with sine and cosine, and the double angle formulas. There are links to...
TeachEngineering
Teach Engineering: Computer Accuracy
Accuracy of measurement in navigation depends very much on the situation. If a sailor's target is an island 200 km wide, sailing off center by 10 or 20 km is not a major problem. But, if the island were only 1 km wide, it would be missed...
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: Geometry: Inverse Trigonometric Ratios
[Free Registration/Login may be required to access all resource tools.] This concept teaches students to use inverse trigonometric ratios to solve for missing angles in right triangles.
Other
Sierra College: Trigonometric Identities
Provides trigonometric identities, which include fundamental identities, even-odd identities, addition formulas, double-angle formulas, subtraction formulas, product-sum formulas, and identities for sin squared and cos squared.
Math Is Fun
Math Is Fun: Geometry
Students learn about geometry by investigating different shapes and their properties. Topics include plane geometry, drafting tools, transformations, angles, and trigonometry.
Other
Gobierno De Navarra: Trigonometria
Use these interactive activities as a supplementary material to visualize some basic concept of Trigonometry.
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.
Cuemath
Cuemath: What Is a Radian?
A comprehensive guide for learning all about radians with definitions, formulas, the arc length formula, angles, the circumference, the radius, solved examples, and practice questions.
Curated OER
Zona Land: Trigonometry Right Triangles
Introduction to right triangles and how to solve them using trigonometric functions. Very nice interactive demonstration of what happens when the angle measurements change and how it effects the calculations. This visual might be just...
Curated OER
Zona Land: Trigonometry Right Triangles
Introduction to right triangles and how to solve them using trigonometric functions. Very nice interactive demonstration of what happens when the angle measurements change and how it effects the calculations. This visual might be just...
Curated OER
Zona Land: Trigonometry Right Triangles
Introduction to right triangles and how to solve them using trigonometric functions. Very nice interactive demonstration of what happens when the angle measurements change and how it effects the calculations. This visual might be just...
Curated OER
Zona Land: Trigonometry Right Triangles
Introduction to right triangles and how to solve them using trigonometric functions. Very nice interactive demonstration of what happens when the angle measurements change and how it effects the calculations. This visual might be just...
Integrated Publishing
Integrated Publishing: The Ambiguous Case
This page from Integrated Publishing discusses the ambiguous case, which arises in trigonometry when you are given two sides of a triangle and the angle opopsite one of them. In an ambiguous case two different triangles could conform to...