Curated OER
Zona Land: Trigonometry, Right Triangles
This site provides information on sine, cosine, and tangent. Lengths of the sides are discussed and many diagrams/tables are shown.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Introduccion a La Trigonometria
This is an interactive activity introducing the concept of trigonometry and working with trigonometric functions to solve right triangles.
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: Law of Sines
[Free Registration/Login may be required to access all resource tools.] Learn how to use the Law of Sines with different types of triangles.
Math Is Fun
Math Is Fun: Introduction to Trigonometry
Students are introduced to concepts taught in trigonometry. The tutorial consists of notes and examples.
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
Brown Math: A 10 Minute Trig Review
Looking for a 10-minute review of the major concepts of trigonometry? This site is a quick recap of degrees and radians, SOH CAH TOA, Pythagorean identities, and special right triangles are all found here.
Lawrence Hall of Science
The Math Page: Trigonometry: Trig Functions of an Acute Angle
Here is a site that clearly and thoroughly explains the trigonometric functions of acute angles within a right triangle. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point...
Math Planet
Math Planet: Geometry: Converse of the Pythagorean Theorem and Special Triangles
The converse of the Pythagorean Theorem is examined through examples and a video lesson. [1:04]
Purple Math
Purplemath: Special Angle Values: 30 60 90 and 45 45 90 Triangles
Explains a simple pictorial way to remember basic reference angle values. Provides other memory aids for the values of trigonometric ratios for these "special" angle values, based on 30-60-90 triangles and 45-45-90 triangles.
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.
Government of Alberta
Learn Alberta: Exploring Similarity and Congruence
Begin by watching this captivating video showing how the concepts of similarity and congruence are found in road signs. Following the video [1:27], an interactive applet allows students to resize, flip, move and rotate triangles to...
Mr. Martini's Classroom
Mr. Martini's Classroom: Right Angle Trigonometry
Explore sine, cosine, and tangents compared to the selected angle.
ClassFlow
Class Flow: Basic Right Triangle Trigonometry
[Free Registration/Login Required] This flipchart shows the basic relationships between trig functions and the sides and angles of a right triangle.
CK-12 Foundation
Ck 12: Trigonometry: Alternate Formula for the Area of a Triangle
[Free Registration/Login may be required to access all resource tools.] An alternate formula for the area of a triangle.
Khan Academy
Khan Academy: Right Triangle Trigonometry Review
Review right triangle trigonometry and how to use it to solve problems.
Math Open Reference
Math Open Reference: Introduction to Trigonometry
An introductory reference guide to trigonometry. It provides definitions and examples that enhance further explanation. Includes links to related topics.
Exploratorium
Exploratorium: Ilion High: Build a Clinometer
Instructions for building a clinometer are given on this page. Clinometers can be used to measure the angle of elevation of a right triangle, and in turn find the height of large objects.
CK-12 Foundation
Ck 12: Trigonometry: Pythagorean Theorem to Classify Triangles
[Free Registration/Login may be required to access all resource tools.] Use the Pythagorean Theorem to determine if triangles are acute, obtuse, or right triangles.
Math Open Reference
Math Open Reference: Tangent (Tan) Function: Trigonometry
Learn about the tangent with this helpful reference tool. Provides a detailed definition, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Mathigon
Mathigon: Geometry: Triangles and Trigonometry: Pythagoras' Theorem
Pythagoras' Theorem: In any right-angled triangle, the square of the length of the hypotenuse (the side that lies opposite the right angle) is equal to the sum of the squares of the other two sides. (A+B=C)
Texas Instruments
Texas Instruments: What's the Trig?
Students will be introduced to right triangle trigonometry. They will use the TI-89 and Geometer's Sketchpad to construct a right triangle and calculate sin, cosine, and tangent of various acute 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.
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...