A man measures the angle of elevation to the top of a mountain to be 12 degrees. He drives 7 miles closer and finds the angle of elevation to be 37 degrees. How high is the mountain?
With y being the distance from where he walked to, to the base of the building, the following proportion can be set up:
3.545193y = 7 + y -------- Cross-multiplying
3.545193y – y = 7
2.545193y = 7
, or 2.750283
Now, height of mountain = =
If familiar with the Law of Sines, you can also use this to find the height. As a matter of fact, this method is easier.