What is defined as an angle with a degree measure less than 90 degrees?

An angle with a degree measure less than 90 degrees is defined as an acute angle. Acute angles are characterized by their sharpness and are commonly found in various geometric shapes and models. Understanding acute angles is essential in mathematics, particularly in geometry, as they are foundational elements for defining more complex figures and concepts.

In contrast, other types of angles have specific characteristics that differentiate them; for example, a right angle measures exactly 90 degrees, an obtuse angle exceeds 90 degrees but is less than 180 degrees, and a straight angle measures exactly 180 degrees. Recognizing these distinctions helps learners grasp the broader concepts of angles and their properties in geometry.