When viewing a higher object from below (by the cat), the acute angle formed by a horizontal eye-lev

Question

When viewing a higher object from below (by the cat), the acute angle formed by a horizontal eye-level and the line of sight is called the angle of elevation. When viewing a lower object from above (by the boy), the acute angle formed by a horizontal eye-level and the line of sight is called the angle of depression. As the horizontal lines are parallel, the value of the angle of elevation is the same as the angle of depression (using alternate angle property). It is always useful to make a sketch of the diagram to determine the position of the objects and the correct angle of elevation and depression. Key concepts needed for right-angled triangles: Trigonometric ratios such as $TOA$, $CAH$, $SOH$ and the Pythagoras' Theorem.

Accepted Answer

Angle of elevation: measured upward from the horizontal. Angle of depression: measured downward from the horizontal. The corresponding angles are equal because the horizontal lines are parallel.

Angles of Elevation and Depression

Angles of Elevation and Depression

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