Answer:
a) 489.77 ft from friend
b) 470.80 ft from cliff
Step-by-step explanation:
Given a man on a 135 ft cliff sees his friend at an angle of depression of 16°, you want to know the distance of the man from his friend, and the distance of the friend from the cliff.
Trig relations
The relevant trig relations are ...
Sin = Opposite/Hypotenuse
Tan = Opposite/Adjacent
Geometry
The 135 ft height of the cliff is modeled as the side of a right triangle that is opposite the angle of elevation from the friend to the top of the cliff. (See attachment 2.) That angle is the same as the angle of depression from the top of the cliff to the friend.
The hypotenuse of the triangle is the distance between the man and his friend. The side of the triangle adjacent to the friend is the distance to the cliff.
Using the above relations, we have ...
sin(16°) = (cliff height)/(distance to friend)
tan(16°) = (cliff height)/(distance to cliff)
Solving for the variables of interest gives ...
distance to friend = (cliff height)/sin(16°) = (135 ft)/sin(16°) ≈ 489.77 ft
distance to cliff = (cliff height)/tan(16°) = (135 ft)/tan(16°) ≈ 470.80 ft
The ma is 489.77 ft from his friend; the friend is 470.80 ft from the cliff.
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Additional comment
The distances are given to more decimal places than necessary so you can round the answer as may be required.
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