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Answer:
24°
Explanation:
The angle between the vertical line AB and the horizontal dashed line at A is 90°. That is, ...
66° + ? = 90°
? = 90° -66° = 24°
The angle of depression is 24°.
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Additional comment
The sum of angles in the triangle is 180°, so the angle at C (the angle of elevation) is the same as the angle we just figured:
∠C + 90° +66° = 180°
∠C +66° = 90° . . . . . . . subtracting 90°; shows C is complementary to 66°
∠C = 90° -66° = 24°
As a rule, the angle of elevation and the angle of depression are the same.