pyramids. The three structures most of
us associate with pyramids were built at
Giza, near Cairo, about 2500 BCE. The
largest of these, the great pyramid of the
pharaoh Cheops, measures 481 feet (147
meters) high. But there are no intricate
pathways in this pyramid; it is merely a
pile of limestone blocks weighing bet-
ween 3 and 15 tons.
Why did the Egyptians choose the
pyramid form? Historians know that the
Egyptian Sun god, with its rays reaching
for the Sun, was represented by pyramid-
shaped stones, or ben-bens. And because
the Egyptians worshipped the Sun as
their chief god, the pyramids are thought
to be huge renditions of the ben-bens.
After a pharaoh died, the pyramids would
be symbolic of the pharaoh ascending the
Sun’s rays to join his Sun god.
Some historians also believe that the pyramids may have had some (still hidden)
numerical significance. In particular, some believe the ratio of the pyramid’s perime-
ter to its height times two, or P/(2 H), gives a close approximation to the value of pi
(π); another claim is that the slopes of the pyramids’ sides were also expressions of pi.
How did people in the Renaissanceapproach architecture?
During the Renaissance, not only mathematics but also architecture made great
strides. In particular, church buildings were no longer based on the shape of the cross,
but rather on the circle. This is because Renaissance architects believed that ancient
mathematicians equated circles with geometric perfection, and that the circle must
then represent the perfection of God.
What was the original useof Stonehenge?
One of the most famous ancient stone complexes is England’s Stonehenge, an impressive
engineering and mathematical feat. Several groups of local inhabitants constructed this
collection of large and small stones grouped in four concentric circles—two of which are
created by paired upright stones bearing huge capstones—between 2950 and 1600 BCE.
Based on how the stones line up with various astronomical events, historians believe the
entire structure represents a huge (literally monumental) calendar. For example, various
stones align with the Moon (the full moon’s extreme positions on the horizon are marked 335
MATH IN ENGINEERING
Cutting a nautilus shell in half reveals chambers
that follow the rules of the golden ratio. It is a beau-
tiful example of how math can be found all around
us in nature. The Image Bank/Getty Images.