Why did the crop circle makers
draw a line at the top of the circles?
Are they trying to explain us something? Again I feel they give us
a puzzle and perhaps here is the solution.
Approximating Pi with
Inscribed Polygons
The circle makers only draw 1 line on top of the circles. I think
it’s a hint.
What I did is drawing 6
other lines on top and 7 lines to the centre of the circle. So now
we have 7 polygons within a circle .
What to do with these polygons?
Well, Archimedes used a fairly simple geometrical approach to
estimate PI.
Around 250 B.C., the Greek
mathematician Archimedes calculated the ratio of a circle's
circumference to its diameter. A precise determination of pi, as we
know this ratio today, had long been of interest to the ancient
Greeks, who strove for precise mathematical proportions in their
architecture, music, and other art forms.
In Archimedes' day, close
approximations of pi had been known for over 1,000 years. An
Egyptian document dated to 1650 B.C., for example, gives a value of
4 (8/9)2, or 3.1605. Archimedes' value, however, was not
only more accurate, it was the first theoretical, rather than
measured, calculation of pi.
How did he do it? The Polygons
in a circle above illustrates Archimedes' basic approach. It finds
an approximation of pi by determining the length of the perimeter of
a polygon inscribed within a circle (which is less than the
circumference of the circle) and the perimeter of a polygon
circumscribed outside a circle (which is greater than the
circumference). The value of pi lies between
those two lengths.
By doubling the number of
sides of the hexagon to a 12-sided polygon, then a 24-sided polygon,
and finally 48- and 96-sided polygons, Archimedes was able to bring
the two perimeters ever closer in length to the circumference of the
circle and thereby come up with his approximation.
Specifically, he determined
that pi was less than 3 1/7 but greater than 3 10/71. In the decimal
notation we use today, this translates to 3.1429 to 3.1408. That's
pretty close to the known value of 3.1416. (For simplicity's sake,
we round off all figures to four decimal places.)
Like Archimedes' approach, our
Polygons in a circle don't rely on specific measurements. The
diameter of the circle is given an arbitrary value of 1; it doesn't
matter if that number represents an inch, a foot, or a light-year.
Also like Archimedes' approach, the interactive determines the
length of a side of each triangle, relative to the diameter, based
on the angle opposing the side being measured.
Our circle and Polygons
differs from Archimedes' approach in three key ways, however. First,
it makes use of algebra and modern trigonometry, which were unknown
in Archimedes' day—Archimedes used geometry instead. For example, he
knew the ratio between one line and another in certain triangles and
with this knowledge was able to figure out the length of the
perimeter of a hexagon.
Second, we use decimal
notation, which wasn't invented until hundreds of years after
Archimedes' death. To work with non-whole numbers, the ancients
relied on ratios. Any calculator will tell you that the square root
of 3 is 1.7321. For Archimedes, that value was 265/153 (which equals
1.7320 in decimal notation).
It
is interesting to note that even today pi cannot be calculated
precisely—there are no two whole numbers that can make a ratio equal
to pi. Mathematicians find a closer approximation every year—in
2002, for example, experts at the University Of Tokyo Information
Technology Center determined the value of pi to over one trillion
decimal places. But this is academic: the value determined by
Archimedes over 2,000 years ago is sufficient for most uses today.
The more Polygons the more precise Pi can be calculated.
That still leaves us with the cubics in
the centre, we can easily notice that the lines on 2 maybe 3 cubics
are not correctly drawn. I still can’t explain this! Perhaps their
software has a bug, or maybe its man made!
© Glenn Aoys Netherlands |