en.wikipedia.org/wiki/Trigonometry

Trigonometry is a branch of mathematics that studies relationships involving lengths and .... These ratios are given by the following trigonometric functions of the known angle A, where a, b and c refer to the lengths of the sides in the ...

www.khanacademy.org/math/geometry/hs-geo-trig/hs-geo-trig-ratios-intro/a/finding-trig-ratios-in-right-triangles

The ratios of the sides of a right triangle are called trigonometric ratios. Three common trigonometric ratios are the sine (sin), cosine (cos), and tangent (tan).

www.khanacademy.org/math/geometry/hs-geo-trig/hs-geo-trig-ratios-intro/v/basic-trigonometry

Intro to the trigonometric ratios. AboutTranscript. Sal introduces sine, cosine, and tangent, and gives an example of finding them for a given right triangle.

www.softschools.com/math/calculus/the_6_trig_ratios

For any right triangle, there are six trig ratios: Sine (sin), cosine (cos), tangent (tan ), cosecant (csc), secant (sec), and cotangent (cot). Here are the formulas for ...

www.varsitytutors.com/hotmath/hotmath_help/topics/trigonometric-ratios

Trigon is greek for triangle, and metric is greek for measurement. The trigonometric ratios are special measurements of a right triangle.

www.purplemath.com/modules/basirati.htm

Demonstrates how to use trig ratios to do simple solving of triangles.

www.ixl.com/math/geometry/trigonometric-ratios-sin-cos-and-tan

Fun math practice! Improve your skills with free problems in 'Trigonometric ratios: sin, cos, and tan' and thousands of other practice lessons.

www.chegg.com/homework-help/definitions/trigonometric-ratios-63

The six trigonometric ratios relate the sides of a right triangle to its angles. Specifically, they are ratios of two sides of a right triangle and a related angle.

mathsfirst.massey.ac.nz/Trig/TrigRatio.htm

Trigonometric Ratios. If one of the angles of a triangle is 90º (a right angle), the triangle is called a right angled triangle. We indicate the 90º (right) angle by ...