(Urgent )!+20! How did Ancient Egyptian construct Pyramid?

Art and design:

A pyramid is any three-dimensional structure where the upper surfaces are triangular and converge on one point. The base of pyramids are usually quadrilateral or trilateral (but generally may be of any polygon shape), meaning that a pyramid usually has three or four sides. The measurements of these triangles uniformly classify the shape as isosceles and sometimes equilateral.
A pyramid's design, with the majority of the weight closer to the ground, means that less material higher up on the pyramid will be pushing down from above. This allowed early civilizations to create stable monumental structures.


Methods (Construction Techniques):

A major problem facing the builders of the Ancient Egyptian Pyramids, was that of getting the Large stone blocks to the height they required. the method shown at left (http://www.touregypt.net/construction), is the only one proven to have been used. The ramps were built on inclined planes of mud brick and rubble. They then dragged the blocks on sledges to the needed height. As the pyramid grew taller, the ramp had to be extended in length, and its base was widened, else it would collapse. It is likely that for the construction of each pyramid, several ramps were probably used.

The arrangement of the ramps used for building is in much dispute. Assuming that the step pyramid was built before the outer structure, and then the packing blocks were laid on top, the ramps could have run from one step to another rather than approaching the pyramid face at right angles.

Some of the pyramids indicate an accurate understanding of Pi, but the mathematical knowledge of the Egyptians did not include the ability to arrive at this by calculation. It is possible that this could have been arrived at "accidentally" through a means such as counting the revolutions of a drum.

The internal construction of most true pyramids consists of a series of buttress walls surrounding a central core. The walls decrease in height from the center outwards. In other words, the core of the true pyramid is essentially a step pyramid. The internal arrangement added stability to the structure. Packing blocks filled the "steps" formed by the faces of the outermost buttress walls and casting blocks (often Limestone) completed the structure of the true pyramid.

Architects and builders used a different form of construction in the pyramids of the 12th and 13th Dynasties. Mainly because of economy, for it was suitable for relatively modest structures in inferior materials. Solid walls of stone ran from the center, and shorter cross walls formed a series of chambers filled with stone blocks, ruble or mud bricks. An outer casing was usually added, and although quite effective in the short term, it did not even come close to the earlier construction methods. Pyramids which were built with this structural design are quite dilapidated and worn.