Right triangle Right triangle A right triangle (American English) or right-angled triangle (British English) is a triangle in which one angle is a right angle (that is, a 90-degree angle). The relation between the sides and angles of a right triangle is the basis for trigonometry. The side opposite the right angle is called the "hypotenuse" (side "c" in the figure). The sides adjacent to the right angle are called "legs" (or "catheti", singular: "cathetus"). Side "a" may be identified as the side "adjacent to angle B" and "opposed to" (or "opposite") "angle A", while side "b" is the side "adjacent to
Hyperbolic triangle In other words, the quantity in the paragraph above is supposed to be equal to 1. Trigonometric formulas for hyperbolic triangles depend on the hyperbolic functions sinh, cosh, and tanh. If "C" is a right angle then: We also have the following equations: The area of a right angled triangle is: also The instance of an omega triangle with a right angle provides the configuration to examine the angle of parallelism in the triangle. In this case angle "B" = 0, a = c = formula_18 and formula_19, resulting in formula_20. The trigonometry formulas of right triangles also give the