What are great-circle arcs?

The correct answer to this question is the intersection of the surface with planes through the center of the sphere. Another name for the great circle is orthodrome. It is the largest circle that can every be drawn in a sphere.

All great circles will have the center and circumference because their diameter coincides with the sphere's diameter. There are two arcs related to the great circle.

One is the minor arc, which is the shortest path between two points in the circle. The major arc is the opposite, which is the longest path between them. This concept is related to the subject of trigonometry.