Which of the following angles is considered to be acute?

An angle is classified as acute when it measures less than 90 degrees. In this case, an angle of 45 degrees falls within that range, making it acute. Acute angles are important in various fields, including geometry and trigonometry, as they are used in shapes, angle relationships, and trigonometric functions.

In contrast, an angle of 90 degrees is classified as a right angle, while an angle of 110 degrees is classified as an obtuse angle, since it exceeds 90 degrees. An angle of 180 degrees is classified as a straight angle, as it forms a straight line. Understanding these classifications is crucial for differentiating between the types of angles and applying their properties effectively.