What is a right angle defined as?

A right angle is defined as an angle that measures exactly 90 degrees. This definition is fundamental in geometry, as right angles are critical in various concepts, including the properties of perpendicular lines, the classification of triangles, and the construction of shapes like squares and rectangles.

In practical terms, a right angle forms a quarter turn and is often represented by a small square in the corner of the angle in diagrams. Understanding that a right angle measures precisely 90 degrees is essential for solving problems related to angles, as it serves as a benchmark for categorizing other angles (acute angles are less than 90 degrees, while obtuse angles are greater than 90 degrees). This knowledge is foundational and allows students to build on more complex geometric principles.