Which angle is characterized by a degree measure of exactly 90 degrees?

An angle that measures exactly 90 degrees is classified as a right angle. This type of angle is significant in various mathematical concepts and real-world applications, serving as a fundamental building block in geometry and trigonometry. Right angles are commonly found in the corners of squares and rectangles, as well as in various construction and engineering designs.

Understanding right angles is essential, as they help establish perpendicular lines, indicating where two lines or edges meet to form a perfect "L" shape. This characteristic allows for precise measurements and layouts in many practical situations, from architecture to artwork.

In contrast, acute angles measure less than 90 degrees, obtuse angles exceed 90 degrees but are less than 180 degrees, and reflex angles measure more than 180 degrees but less than 360 degrees. Each of these types plays an essential role in geometry but does not fit the specific definition of a right angle.