> Hi MJ,
> You responded to Don:
> "The simplest and most obvious explanation for the GP's base
> being an intended 440rc square and an intended 280rc high is
> the seked 5-1/2."
> However, that's not what he was wondering about. Don posited,
> "Over the years we have often tried to figure out why did the
> builders choose 440."
> No slope has any bearing on the choice of number of cubits for
> the GP base.
> Just a friendly clarification. :)
With respect, your ‘friendly clarification’ is actually no more than your personal considered opinion.
Don asked why the intended (?) length of the Great Pyramid’s sides at the base is 440rc.
I suggest that the answer is because the intended horizontal distance from a side at the Pyramid’s base to the centre of the base (seen also as: to the apex of the Pyramid) was intended to be 220rc, and twice 220rc is 440rc.
But this begs the question: why 220rc?
Here we need to bring in the intended (?) vertical height of the Pyramid, which is 280rc.
So, in the Pyramid we have a right-angled triangle with a horizontal base @ 220rc and a vertical height @ 280rc.
Now, note how the gradient and length of the Pyramid’s sloping faces are irrelevant here because both are the natural product of a right-angled triangle with a vertical height @ 280rc and horizontal base @ 220rc.
According to the Egyptian Mathematical Papyri (EMP) Seked 5-1/2 was normally expressed as 1 royal cubit rise to 5-1/2 palms horizontal run.
I suggest that the Pyramid’s architect saw seked 5-1/2 also in the terms 28 digits vertical rise to 22 digits horizontal run, and this led him to 280rc vertical rise to 220rc horizontal run for the key dimensions of the Pyramid – resulting in a length of the Pyramid’s sides at its base @ 440rc.
Again, note how the gradient and length of the Pyramid’s sloping faces are irrelevant here.
But why did the architect choose seked 5-1/2?
Well, further to what I wrote previously on this question; there is no disputing that the intended vertical height of the Pyramid is to the intended perimeter of the base as a circle’s radius is to its circumference @ 3-1/7.
In my theory on the planning of the Great Pyramid and its passages and chambers, etc., I give 40-plus occurrences of multiplication or division by the equivalent of 3-1/7.
But did the architect see and employ this equivalent of 3-1/7 as pi?
I, perhaps surprisingly, am not convinced that he did.
I suggest that we are looking at a basic 1) Dimension A = Dimension B multiplied by 22, and divided by 7; and 2) Dimension A = Dimension B multiplied by 7, and divided by 22.
I see the number of palms in the rise of seked 5-1/2 as the source of the multiplier/divider 7, and the number of digits in the horizontal run of seked 5-1/2 as the source of the multiplier/divider 22.
Hence, instead of, for example, Dimension A = Dimension B multiplied by 3-1/7, we have: Dimension A = Dimension B multiplied by the number of digits in the horizontal run of seked 5-1/2 @ 22, and divided by the number of palms in the rise of seked 5-1/2 @ 7.
Yes, this is all very laboured and cumbersome by our standards, but as anybody who has read the EMP knows, the AEs seemed to like their maths being laboured and cumbersome.
> As a side note, I (kindly) don't agree with Don's intriguing
> view on the 440 -- I believe it was chosen to fit a
> processional reference which incorporates all the pyramids.
Hmm, guess who doesn’t agree with this processional business. 
When it comes to the ‘mysteries’ of the Ancients, I am guided first and foremost by Occam ’s razor.
So few answers - and not one of them mine.