What type of angle is exactly 90 degrees?

A right angle is defined as an angle that measures exactly 90 degrees. This specific measurement is significant in geometry because it indicates a perfect quarter turn, which is critical in constructing perpendicular lines and various geometric shapes.

A right angle can be commonly observed in many practical contexts, such as in the corners of squares and rectangles, and serves as a foundational concept in many areas of mathematics, including trigonometry and the calculation of angles in various polygons.

In contrast, acute angles measure less than 90 degrees, obtuse angles measure more than 90 degrees but less than 180 degrees, and straight angles measure exactly 180 degrees. Understanding these distinctions helps clarify the properties and classifications of angles in geometric studies.