Assessment and Learning in Knowledge Spaces (ALEKS) Practice Exam

What is an angle's complement?

1. The angle that results when it is added to a straight angle

2. The angle that, when added to it, results in a right angle

3. The angle formed between two intersecting lines

4. The angle opposite to a given angle in a triangle

The correct answer is: The angle that, when added to it, results in a right angle

An angle's complement is defined as the angle that, when added to the original angle, results in a right angle, which measures 90 degrees. For instance, if you have an angle measuring 30 degrees, its complement would be 60 degrees because 30 + 60 = 90. This is a fundamental concept in geometry, particularly when dealing with angles in various contexts, such as right triangles or the relationships between different angles in geometric figures. Understanding the concept of complementary angles is essential, as it is frequently applied in solving problems related to angles, trigonometry, and various geometrical proofs. This relationship is unique to right angles, differentiating it from other types of angles, such as those formed by intersecting lines or angles within a triangle.