Which type of triangle is defined as having one right angle?

A triangle defined as having one right angle is classified as a right triangle. The defining characteristic of a right triangle is that it contains exactly one angle measuring 90 degrees. This property is significant in various mathematical applications, such as trigonometry, where the relationships between the sides and angles of triangles are fundamental.

In contrast, equilateral triangles have three equal sides and three equal angles, each measuring 60 degrees, meaning they cannot contain a right angle. Scalene triangles are characterized by having all sides of different lengths and all angles of different measures, which does not necessarily include a right angle. Isosceles triangles feature at least two equal sides and their opposite angles are also equal, but they may or may not contain a right angle depending on their specific dimensions. Each type of triangle has unique properties, but only the right triangle is explicitly defined by the presence of a right angle.