What is a right triangle defined by?

A right triangle is specifically defined as a triangle in which one of the angles measures exactly 90 degrees, which is known as a right angle. In this type of triangle, the two sides that form the right angle are referred to as the legs, while the side opposite the right angle is known as the hypotenuse. This definition emphasizes the crucial element of having a right angle, distinguishing it from other types of triangles.

In contrast, acute triangles only contain angles that are less than 90 degrees and do not include a right angle. Triangles with sides of equal length are classified as equilateral triangles and can have angles of varying measures, but one of those angles cannot be a right angle. Lastly, a triangle with one obtuse angle contains an angle greater than 90 degrees, ruling out the possibility of containing a right angle. Therefore, the defining feature of a right triangle is the presence of a right angle created by two sides meeting orthogonally.