We have been given that a campsite is 12.88 miles from a point directly below Mt. Adams. The angle of elevation is 15.5° from the camp to the top of the mountain. We are asked to find the height of the mountain.
We can see from the attachment that h is opposite side to angle 15.5 degrees and 12.88 miles in adjacent side.
We know that tangent relates opposite side of right triangle with its adjacent side.
Therefore, the mountain is approximately 3.57 miles high.