Question

Is angle of elevation always measured from the HORIZONTAL AXIS?

Answer 1

Angle of elevation = angle of depression.

Explanation:

The same goes for the angle of depression - it is also always measured from the horizontal but looking downwards.

The angle of elevation and the angle of depression in any scenario are always EQUAL.

One person looks UP, the other person looks DOWN, but the angles are equal alternate angles because horizontal lines are always parallel.

Another aspect to note: if you sketch the scenario and show a right-angled triangle, Only ONE of the them can be in the triangle.

Of the angle of elevation and angle of depression, one is INSIDE the triangle, the other is OUTSIDE the triangle, but there are two congruent triangles which can be drawn.

Draw in a horizontal line of sight first, and work from that!