Angle of Depression

An angle of depression is the measure of an angle from the horizontal to the line of sight as a person is looking down at an object. See the drawing below.


In the diagram above, the sight line is the segment from the eye (P) to the object (R) and the measure of the angle from the horizontal to the sight line is the angle of depression.  In order to use trig functions within situations involving the angle of depression, draw a vertical line from the object to the horizontal line creating the right triangle.