In geometry, how many degrees are in a right angle?

A right angle measures exactly 90 degrees. This fundamental concept is a cornerstone in geometry and is essential for understanding various geometric shapes and properties. A right angle is formed when two lines meet in such a way that they create four equal angles, each measuring 90 degrees.

In practical terms, right angles are typically visualized with the corner of a square or rectangle, where the sides meet to create that perfect 90-degree bend. This characteristic is crucial in numerous applications, including architecture, carpentry, and various forms of design, where precise angles are needed to ensure stability and correctness.

The other angles provided do not relate to the definition of a right angle. For instance, 45 degrees represents an acute angle, which is less than a right angle, while 180 degrees signifies a straight angle formed when two rays point in exactly opposite directions. A full rotation of a circle is 360 degrees, which encompasses all possible directions around a point and doesn't define a right angle at all. Knowing that a right angle is specifically 90 degrees allows individuals to correctly classify and work with angles in various geometric contexts.