Right triangle 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. If, for a given angle α, the opposite side, adjacent side and hypotenuse are labeled "O", "A" and "H" respectively, then the trigonometric functions are For the expression of hyperbolic functions as ratio of the sides of a
Automedian triangle satisfying the formula "a" = "b" + "c". That is, in order for the three numbers "a", "b", and "c" to be the sides of an automedian triangle, the sequence of three squared side lengths "b", "a", and "c" should form an arithmetic progression. If "x", "y", and "z" are the three sides of a right triangle, sorted in increasing order by size, and if 2"x" < "z", then "z", "x" + "y", and "y" − "x" are the three sides of an automedian triangle. For instance, the right triangle with side lengths 5, 12, and 13 can be used