Points A and B are on the same horizontal line with the foot of a hill and the angles of depression of these points from the top of the hill are 35° and 25°, respectively. If the distance between A and B is 75 m, what is the height of the hill?

Answer 1

a diagram and a review of the basic trig functions should convince you that the height h of the hill is found via

h cot25° - h cot35° = 75

Answer 2

h cot25° + h cot35° = 75

Answer 3

hmmm. It appears we disagree on whether A and B are on the same side of the hill. Since we're talking about a hill, and not a pole, I stick by my interpretation -- heck -- I even have a drawing to show it!