For the already paranoid among us :)

[NorthernRaider]

Lets look at this sensibley the pyramids average age is 3000 years old, the Imperial measurement system was not developed until 1824 and the Metric system was not developed until 1799. the Egyptians could not in a thousand years use those sytems of measurement.

as for pointing north WHICH north, Grid North, True North, Magnetic North? True north and Mnorth both vary over millenia cos of polar axis wobble and the movement of the magnetic core in the earth and the Grid north was only designated in the late 17th century.

The north star that many ancient cultures used a point of reference also moves.