That's interesting because, due to seafloor spreading, the geographic center of the earth's land area is very slowly moving northwestward. But the spreading since the building of the pyramids has been negligible (much less than a kilometer).
More important over the span of human history would be changes in sea level. At the height of the last ice age, about twenty thousand years ago, sea level was about 100 meters lower than it is today. This would have a significant effect on land area distribution.
More interesting you've where the geographic center of the pyramids and "stones":
the coordinates are latitude 18 deg 8 min North and longitude 99 deg 33 min West ( 40 miles from Mexico City ). This is "sun fire pyramid" from 07/25/2005 "tzolkin zero".
You center should surface from "babilonian"
the geographic center , the coordinates are latitude 32 deg 48 min North and longitude 44 deg 48 min East.
Giza, the coordinates are latitude 29 deg 88 min North and longitude 31 deg 69 min East.
"black stone", the coordinates are latitude 21 deg 48 min North and longitude 39 deg 78 min East.
Have you better coordinates? Then write are.
This depends on the bounds you to set to define the problem in the first place. If you take the last 15 degree of arc off the west edge and add it to the east edge. The calculation changes???? Same applies to north south direction. The answer depends on your arbitary start view of the 2D coordinate set.
Start pont is arbitary and is just a "convention" for practical reasons that poles are 90 lat, and 0 E/W passes through a particular point so east west limits on projection are 180E, 180W. This does not need to be. Change this convention and answer would be different.
Very Europe centric answer. Near the centre of the arbitary bounds. You could make it Indian, NEMA, Latin American, South East Asian, Polynesian or even Bermuda centric by changing the start view. Please play the "lost in space" theme at this point.
The 2D coincidence in the med is only the arbitary start. The real 3D centroid based on area at the surface exclusive of convention would be kinda hot.