Final answer:
At the North Pole, Polaris appears directly overhead at an altitude of 90 degrees above the horizon line, since the altitude of the north celestial pole is equal to the observer's latitude.
Step-by-step explanation:
If you are at the North Pole, which is at a latitude of 90 degrees North, Polaris will be directly overhead. The altitude of Polaris above the horizon line will be 90 degrees. This is because the altitude of the north celestial pole in the sky is equal to the latitude of the observer. Therefore, standing at the North Pole means that the north celestial pole, and Polaris which is very close to it, are at your zenith, which is directly above you.