Since the problem is not telling us the height of Silvio, we are going to assume it is not relevant for our calculations.
Let
the altitude of the incoming plane. We know for our problem that the distance between Silvio and the tower is 3 miles, Also we know that the angle of elevation to the plane is 40°. With this information we can create a triangle as shown in the figure. We need a function that relates the angle of elevation with its opposite and adjacent sides, that function is tangent.
We can conclude that we should use the trig function tangent to model this situation; also, we can conclude that the equation that describes this situation is.
Let
We can conclude that we should use the trig function tangent to model this situation; also, we can conclude that the equation that describes this situation is