Today I learned
Latitude of the Great Pyramid of Giza ~= 29.9792458° N (within reasonable error bars)
Whereas speed of light ~= 299,792,458 m/s
It's just a coincidence.
As to the claim that the meter was invented relatively recently, its original definition was one ten-millionth of the distance from the equator to the North Pole, so in theory peoples from other cultures could have used a similar definition with similar values.
The coincidence is still very very uncanny.