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
Integer triangle or right triangles because all resulting angle combinations generate angles with non-rational sines, giving a non-rational area or side. All isosceles Heronian triangles are decomposable. They are formed by joining two congruent Pythagorean triangles along either of their common legs such that the equal sides of the isosceles triangle are the hypotenuses of the Pythagorean triangles, and the base of the isosceles triangle is twice the other Pythagorean leg. Consequently, every Pythagorean triangle is the building block for two isosceles Heronian triangles since the join can be along either leg. All pairs of isosceles Heronian triangles are given by rational