How many degrees are in a right angle?

A right angle is defined as an angle that measures exactly 90 degrees. This is a fundamental concept in geometry, as right angles are used to create perpendicular lines and serve as a benchmark for other angles.

In contrast, the other options represent different types of angles. An angle measuring 45 degrees is considered an acute angle, which is less than a right angle. An angle measuring 180 degrees is classified as a straight angle, which forms a straight line. Lastly, an angle of 120 degrees is an obtuse angle, being greater than a right angle but less than a straight angle. Understanding these definitions is crucial for comprehending various geometric principles and applications.