The North Pole radius is how many mm longer than the South Pole radius?

Question

Earth is not round ; it is slightly pear-shaped.

Answer 1

The earth is pear shaped.
http://www.mckinleyville.com/cart/cabinet/cab_math.html
http://www.geo.ucalgary.ca/~macrae/t_origins/earth_shape/earth_shape.html
http://www.geo.ucalgary.ca/~macrae/t_origins/earth_shape/talbott_earthshape.html
In grammar school, most of us learned that the earth was not a perfect sphere, but something called an "oblate spheroid," having a greater diameter at the equator due to the earth's spin and bulging somewhat in the southern hemisphere in a manner reminiscent of a middle age spread. In all, this pear-shaped earth did not differ in equatorial and polar radius by more than 15 miles, but this in itself was important to know. Now it is being found that the earth is gradually "rounding itself out" again.

http://www.gi.alaska.edu/ScienceForum/ASF6/629.html

Answer 2

Earth is not pear-shaped. Earth is shaped like a sphere that has been stepped on and squished slightly. It bulges at the equator.

The north pole does not have a radius. The north pole is just one of the two points on the surface of the Earth that the Earth's axis of rotation passes through. Your question doesn't make sense.