Yu need two lines or planes for an angle "between". Only one has been specified in the question.
Chat with our AI personalities
A horizontal angle is an angle between lines on a horizontal plane.
angle of depression.
Angle of depression is the angle between a horizontal line and the line joining the observer's eye to some object beneath the horizontal line. ^_^
this is horizontal: ---------------------------- / / this is at an angle: / / /
It is called the displacement in the horizontal direction.