Trilateration using 3 latitude and longitude points, and 3 distances

Question

There exists an unknown target location (latitude and longitude co-ordinates). I have 3 latitude and longitude co-ordinate pairs and for each pair a distance in kilometers t

Answer 1

I asked this question on the newly-formed GIS Stack Exchange, and got some good answers there as well.

https://gis.stackexchange.com/questions/66/trilateration-using-3-latitude-and-longitude-points-and-3-distances

The accepted answer there has a (presumably) working solution in Python:

https://gis.stackexchange.com/questions/66/trilateration-using-3-latitude-and-longitude-points-and-3-distances/415#415