Answer:
27 degrees
Step-by-step explanation:
First, we can draw this out. Since the altitude is 8000, we can make that the height, and it goes 16000 feet through the air, that can be the length. I have drawn this out, as shown in the image. Note that when drawing, because the airplane is going up and forward, that path should represent the hypotenuse. The angle of elevation is the angle connecting the length and the path, as shown by the angle x in the picture.
We know than tan(x) = opposite/adjacent, so tan(x) here = 8000/16000 = 1/2. Then, arctan(1/2) =x = 27 degrees
