You are standing in front of a building and you want to measure its height. How will you do that? It is definitely not possible to measure it directly. Trigonometry helps do that. You can use angle of elevation and depression to measure heights and distances easily which are otherwise complicated to measure.
Angle of elevation
The angle of elevation of the point being viewed is the angle formed by the line of sight (line of vision of the observer) with the horizontal, when the point being viewed is above the horizontal level i.e., the case when we raise our head to look at the object.
Angle of depression
The angle of depression of a point on the object being viewed is the angle formed by the line of sight with the horizontal when the point is below the horizontal level, i.e., the case when we lower our head to look at the point being viewed.
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