The drawing shows a person looking at a building on top of which an antenna is mounted. The horizontal distance between the person's eyes and the building is 85.0 m. In part a the person is looking at the base of the antenna, and his line of sight makes an angle of 35.0 with the horizontal. In part b the person is looking at the top of the antenna, and his line of sight makes an angle of 38.0 with the horizontal. How tall is the antenna?

Answer 1

85 (tan 38 - tan 35) meters

This is more of a trigonometry than a physics question.

Answer 2

the question is a bit ambiguous in not specifying whether line of sight is UP from the horizontal or DOWN. the correct answer could be:
h = 85m[tan 38deg + tan 35deg]
...if the observer is in a window of a nearby building or on a hilltop, etc.
[many professors are ambiguous because they know the answer THEY want.]