What characterizes an obtuse triangle?

An obtuse triangle is defined by the presence of one angle that measures greater than 90 degrees, which is referred to as an obtuse angle. This characteristic is unique to obtuse triangles, as it differentiates them from other types of triangles. For instance, in a triangle that has three equal sides, it would be classified as an equilateral triangle and cannot contain any obtuse angles. Similarly, a triangle with three acute angles would be classified as an acute triangle. Lastly, a triangle that has a right angle is classified as a right triangle. Therefore, the defining feature of an obtuse triangle, having one obtuse angle, accurately captures its essence and differentiates it from the other types of triangles.