In Euclidean geometry, the perpendicular bisectors of the sides of a triangle are concurrent at the CIRCUMCENTER, the point equally distant from the triangle vertices, and the center of the circumscribed circle. The sketch below illustrates the construction of the perpendicular bisectors of a spherical triangle. They, too, are concurrent at point O, the center of the circumscribed circle. Essentially, the circumcircle is a circle of latitude with point O as the pole.
Drag points A, B, and C slowly.
