The drawing shows the classic Pyramid internal room lay out: in a vertical plane , orientated north to south direction.
This plane is not perfectly in the centre of the Pyramid, but it is shifted 7,2 m east side.
(I add this note after the event: the measure, given by Maragioglio e Rinaldi, is not a whole multiple of the cubit, measure used at that age, and this was strange to me. Just from a while I found that is wrong. A recent survey, made by R. Gantenbrink, affirms the length is 6,82 m. That is a logic right measure, equal to 13 cubits exactly).
I suppose this asymmetry was made to create difficulties to the tomb raiders.
This hypothesis is not new, nor mine only.
I’m not an experienced specialist in Ancient Egypt matters and I don’t know exactly what has been already written about any part of my theory. That means something could be known, since long time. Please, forgive me if, sometimes, I may suppose to be the first to approach the problem from a different point of view.
Now I try to give you a briefly description of my hypothesis.
Back to the internal map: a straight passage starts from the main entrance, going down with a constant angle of 26,5 degrees.
This is a very important angle for two reasons, and we will find it again in the upper passage, in the Grand Gallery and in many other pyramids or tombs where the closure have been made by a train of square stone blocks, sliding down a slope.
First reason: putting a smooth square block on a slope and increasing the slope angle, first or later, the block will start slipping. The ultimate stability angle is connected to the friction (forget about static or dynamic: I’m not at school!) between the two surfaces, smaller or bigger depending from the smoothness, if any kind of lubricant is present, etc.
I have prepared a very simple slope in the school lab and , using a granite block, not very smooth really, I tested that, the closest is the angle to 26,5°, the easiest the block will start slipping down. At last, a very small force is enough to move the block down, not to stop it anymore.
Second reason: why this kind of angle has been used so often? It is very easy to reproduce it! We must remember that, although skilled workers, people that built the pyramids had very little theoretical knowledge of geometry.
Strangely enough, if we make a step 10 cm high and 20 cm wide, we will get a triangle easy to reproduce; in fact, if the proportion between height and width will remain always the same (that means 1 to 2) the angle will have still the same value, 26°,56 (for mathematics INV TAN 0,5= 26°,56): this is really a good chance.
So this angle is perfect.
Of course the block surfaces had to be very smooth and any kind of liquid substance like oil, water, etc., poured on the contact area, might help moving.
Let’s go back to the descending passage: it was built positioning stone blocks for 30,28 m. in length, subsequently it goes down like a trench,excavated in the limestone, where the Pyramid has been built on.
The size of the passage is strictly constant along the entire length and it could be helpful to transform the dimensions into the measures used in the Ancient Egypt.