Scientists, geographers, and navigators, among others, use an imaginary grid laid on top of Earth to pinpoint a specific geographic area.
You can see the horizontal lines (latitudes) and vertical lines (longitudes) on almost all maps and globes. Latitude measures points north and south; longitude measures points east and west.
Latitudes measure the angular distance of a point between the North or South Pole and the equator. Imagine bisecting Earth at the equator.
One arm of your angle reaches out from the center of Earth to the equator. The other arm of the angle can point to any other place on Earth—the equator is a 0° angle and the geographic North and South Poles are 90° angles.
Take New York City, for example. The three points of your angle would be on the center of Earth, the equator, and New York City, respectively. The measure of the angle is 40°. New York City is, therefore, 40° north latitude.