Editing Right triangle (section)

==Trigonometric ratios==
{{main|Trigonometric functions#Right-angled triangle definitions|l1=Trigonometric functions – Right-angled triangle definitions}}

The [[trigonometric functions]] for acute angles can be defined as ratios of the sides of a right triangle. For a given angle, a right triangle may be constructed with this angle, and the sides labeled opposite, adjacent and hypotenuse with reference to this angle according to the definitions above. These ratios of the sides do not depend on the particular right triangle chosen, but only on the given angle, since all triangles constructed this way are [[similar triangles|similar]]. If, for a given angle α, the opposite side, adjacent side and hypotenuse are labeled <math>O,</math> <math>A,</math> and <math>H,</math> respectively, then the trigonometric functions are
:<math>\sin\alpha =\frac {O}{H},\,\cos\alpha =\frac {A}{H},\,\tan\alpha =\frac {O}{A},\,\sec\alpha =\frac {H}{A},\,\cot\alpha =\frac {A}{O},\,\csc\alpha =\frac {H}{O}.</math>

For the expression of [[hyperbolic function]]s as ratio of the sides of a right triangle, see the [[hyperbolic sector#Hyperbolic triangle|hyperbolic triangle]] of a [[hyperbolic sector]].