Here's how to determine the latitude line halfway between Ecuador and the North Pole:

* Ecuador's Latitude: Ecuador lies at 0 degrees latitude, the equator.

* North Pole's Latitude: The North Pole is at 90 degrees north latitude.

* Midpoint: To find the midpoint, calculate the average: (0 degrees + 90 degrees) / 2 = 45 degrees.

Therefore, the latitude line halfway between Ecuador and the North Pole is 45 degrees north latitude.