Hey there!
So in this case, you would need to use the tangent function to find out the height needed to begin the descent.
Assuming that the plane is 30,380ft from the runway horizontally, we would insert that for the adjacent value. We need to find the opposite value in this case to find the height of the aircraft.
Recalling that the tangent of an angle equals the opposite side over the adjacent side, our equation would be as follows:
tan 3 = (x/30380), where the angle is equal to 3, the opposite value we don't know so we put as "x", and the horizontal adjacent side is the distance, 30,380ft.
Using algebra to get x by itself, we would write the equation like this:
30380(tan 3) = x.
Your answer should be approximately 1589.96ft.
Hope that helps!
