In: Advanced Math
Discuss the ratio of circumference to diameter for circles on the sphere.
the Euclidean radius is the distance to the (Euclidean) center
of the circle -- which
is not a point on the sphere. But the circle also has a center on
the
sphere -- this would be the North (or South) Pole for lines
of
latitude. So the spherical radius of such a circle is different,
namely
the spherical distance from the (spherical) center.
Derive formulas relating these various notions of radius
and circumference.