What do the angles of elevation and depression refer to?

Angles of elevation and depression are specific angles measured from the horizontal line. The angle of elevation refers to the angle formed when an observer looks upward from a horizontal line to an object above, whereas the angle of depression is formed when the observer looks downward from a horizontal line to an object below.

When considering the geometry of these angles, it becomes evident that they are indeed vertical angle measurements, as they are defined in relation to a horizontal reference line. This conceptualization is fundamental when solving problems in trigonometry, where these angles are used to determine heights or distances in various applications. Understanding this allows students to apply relevant trigonometric functions, such as tangent, sine, and cosine, to solve real-world problems.

The other choices do not accurately describe the nature of angles of elevation and depression, which focus specifically on the relationships between horizontal lines and vertical angles related to objects above or below the observer's line of sight.