Which of the following accurately defines a right triangle?

A right triangle is accurately defined as a triangle that has one right angle, which measures exactly 90 degrees. This unique characteristic distinguishes right triangles from other types of triangles. In the case of a right triangle, the presence of a right angle allows for the use of various geometric principles, such as the Pythagorean theorem, which relates the lengths of the sides of the triangle.

Understanding what a right angle is and its role within the triangle is fundamental to identifying right triangles. While triangles can come in different forms, a right triangle specifically necessitates this one right angle, differentiating it from equilateral triangles, which have three equal sides, and obtuse triangles, which possess one angle that is greater than 90 degrees. Therefore, the definition that highlights the presence of a right angle is the correct one.