An observer (o) is located 500 feet from a school (s). the observer notices a bird (b) flying at a 39 degree angle of elevation from his line of sight. how high is the bird flying over the school?

Were using a right angle to show this. The angle of elevation is 39 so the base angle is going to be 39. the point a this angle is O where the observer is. the school is 500 feet from the school so this is gonna be the base and in this case the adjacent leg. You are trying to find the height the bird is flying which is represented by the opposite leg of the triangle. Since you have the opposite and adjacent legs you use tangent. Tan39=x/500 because of the formula for tangent. So X=500* tan39, so it is flying about 404.89 feet above the school