Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 4 - No. 4)
In a diagram showing the angle of elevation and the angle of depression, which lines are considered parallel?
The line of sight and the horizontal plane.
The horizontal plane and the vertical.
The two lines of sight.
The vertical and the line of sight.
Explication
The horizontal planes are parallel to each other.