"The datum of Goyon that is 102.2m or about 196 cubits, differs from those of Vyse and Petrie, but we do now know how the French scholar obtained this measurement since the west face, which he examined, is much obstructed and covered with sand. As appears from the text, where it is said that each block of the first course has a different laying level, the elements are lacking to determine what the level of the surrounding courtyard was, so that the system adopted by Petrie seems to us rational enough. Perhaps Goyon found some features which enabled him to determine the level of the courtyard: only in this case could his measurement be exact. As far as we are concerned, for lack of this certainty, since the ancient Egyptian builders normally planned the length of the base side of the pyramids as a round number of cubits, we think that in the case of Mycerinus the finished pyramid was designed to have a base of 200 cubits (104.6m) while not denying that on the spot it may have turned out to be some cubits more or less." (Maragiglio & Rinaldi Vol VI p.96)

Other factors seem to contributed to the confusion. Edwards's measurements for Giza are usually Petrie's but converted to feet and inches and rounded to the nearest inch. For Menkaure this should be 346" 1' but he quotes 356" 6' and I have seen this suggested as a misprint which has gone on to be converted to metre's and published elsewhere.

Then there's the general problem of the sides being measured at different heights above the pavement which led to the odd oblong measurement in Lehner when two sets of measurements were combined (this was confirmed to me in a private email correspondence that I can't quote).

I think the safest thing that can be said is that the pyramid was meant to be square and Petrie's measurement is probably best used with the caveat that his method for establishing the pavement height must be kept in mind.

Jon

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