Curated OER
Trig functions and Triangles
Here is a basic plan for the beginning teacher to use for introducing the class to the right triangle trigonometric functions. It outlines the lesson plan objectives, class procedures, and basic instructional techniques that could be used.
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.
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Trigonometric Ratios
Find a quick, concise explanation of the trigonometric ratios: sine, cosine and tangent. Examples are given and clearly explained.