I used Coles data for this.
The surveyors told me that latitude ie the distance north or south from the equator increased slightly the further north or south you go. At he equator it is approximately 68.7 miles 110.558km while at the pole north or south the distance measured 69.4 miles or 111.685km not exactly but approximately.
They gave me the program on a 'floppy disk' don't know if you have heard of it but long gone. Anyway I asked the distance from the equator to 30 seconds north as I had read that the Great Pyramid was said to have a perimeter equal to 30 seconds of 1 degree.
The surveyors gave me this 'One half minute (30 secs) of Equatorial Latitude equals 3023.12 feet or 921.45 metres.'
As you know according to Cole's data the perimeter of the pyramid = 3023.13 feet or 921.453 metres.
Wether by accident or design the perimeter of the Great Pyramid = 30 seconds of latitude measured from the equator to 30 seconds north.
Hopes this help's in your research.