Pi Day is celebrated on March 14th (3/14) in honor of the mathematical constant π (pi). Pi is the ratio of a circle's circumference to its diameter and is approximately 3.14. Archimedes calculated pi to a very close degree by determining the length of a polygon inscribed within a circle and dividing by the diameter. The largest calculation of pi digits was over 1 trillion digits by a Japanese supercomputer in 2002. Pi is involved in formulas relating to areas and volumes of circles, spheres, cylinders, and cones.

1. Pi Day
3-14
π = 3.14159265358979323846264...
March 14th
is

2. The Definition of Pi
• Pi, not Pie.
• 1.The 16th
letter of the Greek alphabet is P or p,
corresponding to the roman p.
• 2. A number, represented by said letter,
expressing the ratio of the circumference of a
perfect circle to its diameter. The value of pi has
been calculated to many millions of decimal
places, to no readily apparent pattern.

3. Beginning of Pi
• It occurs in a list of specifications for the great
temple of Solomon, built around 950 BC and its
interest here is that it gives π = 3. Not a very
accurate value of course and not even very accurate
in its day.

4. Beginning of Pi
• The earliest values of π
including the 'Biblical'
value of 3, were found
by measurement. In the
Egyptian Rhind
Papyrus, which is
dated about 1650 BC,
there is good evidence
for 4(8/9)2 = 3.16 as a
value for π.

5. Archimedes
(Known for his work with Pi)
• 287 BC – 211 BC
• Spent most of his life in Syracuse, Sicily.
• Studied in Alexandria, Egypt under the
followers of Euclid.

6. Archimedes
• Invented War Machines used in the defense of
Syracuse, compound pulley systems,
planetarium, water screw, water organ, burning
mirrors.

7. Archimedes
• Generally regarded as the greatest
mathematician and scientist of antiquity.
The “father of integral calculus.”

8. Archimedes
• Archimedes calculated pi to a very close
degree, how?
He found an approximation of pi by determining
the length of the perimeter of a polygon inscribed
within a circle and dividing it by the diameter of
the polygon. A reconstruction model is here

9. How Many Numbers?
• 1699 – Only 71 digits were correctly
discovered.
• 1719 – 112
digits were
found to be
correct in
France.

10. How Many Numbers?
1841 – 440 were calculated in England.
1946 – 620 digits were correctly ordered.

11. Pi Facts
• So far, the largest count of Pi was done by a
supercomputer at the University of Tokyo in Sept of
2002. 1.2411 trillion decimal digits were calculated.
That looks like 1,241,100,000,000 numbers

12. Pi Facts
• There are no repeating parts in Pi. This means
that at no part during the 1.2411 trillion counts of
Pi did the pattern begin to repeat itself. It is the
only number like this in the world.
• Albert Einstein was born on Pi Day in 1879

13. Pi Facts
• No perfect circles or spheres exist in nature, since
matter is composed of atoms and therefore lumpy, not
smooth. So, the approximation of Pi may not be as
close to 3.14…

14. Pi Facts
• The worlds largest pie was made in
Traverse City, Michigan. It was 17 feet,
6 inches in diameter and weighed
28,350 pounds. It was a cherry pie.

15. Pi Facts
• Pi Day begins at precisely 1:59 p.m.
on March 14. It reads 3/14/1:59
which corresponds to 3.14159…

16. Pi Facts
• Pi is the first letter in the Greek word
meaning perimeter.
• The time it takes for a planet to orbit the
sun has Pi involved. Here is a diagram for
the way planets orbit.

17. Pi Equals?
• π = circumference/diameter
≈ 3.14
• π ≈ 22/7 or 3 and 1/7

18. Use Pi to Find:
• The area of a circle = πr2
• Circumference of a Circle = πd or 2πr
• Surface Area of a Sphere, Volume of a
Cone, Cylinder and Sphere all are
formulas that involve π.

19. Use Pi to Find:
Right Cylinder – V = πr2
h
SA = 2πr2
+ 2πrh
Right Cone – V = 1/3 πr2
h
SA = πr (l + r)
Sphere – V = 4/3 πr3
SA = 4πr2

20. Fun With Circles
• This 12-ton, 80-foot-tall behemoth was built
to withstand hurricane-force winds, and
served as a ferris wheel (and a huge
advertisement for Uniroyal) at the 1964-65
New York World's Fair. Twenty-four gondolas
circled the tire where the treads are today,
carrying nearly two million people.

21. Fun With Circles
• Colossus is an 18-
story Ferris Wheel.
This giant wheel
puts guests' heads
in the clouds, as
well as giving a
breathtaking view
of the entire park.
At night, Colossus
puts on a show of
its own with more
than 2,000 lights.
It is 165 feet in diameter and has a
circumference of 518 feet.518ft / 165ft ≈ 3.139, which
is almost pi.

22. What is "pi"?
• Mathematician: Pi is the ratio of the circumference of a circle to
its diameter.
• Engineer: Pi is about 22/7.
• Physicist: Pi is 3.14159 plus or minus 0.000005
• Computer Programmer: Pi is 3.141592653589 in double
precision.
• Nutritionist: You one track math-minded fellows, Pie is a
healthy and delicious dessert!

23. Pi Jokes
Q: What do you get if you divide the
circumference of a jack-o-lantern by its
diameter?
A: Pumpkin Pi.
Q: What do you get when you take a
native Alaskan and divide its
circumference by its diameter?
A: Eskimo pi.

24. Pi Jokes
Q: What do you get when you take the
sun and divide its circumference by its
diameter?
A: Pi in the sky.
Q: What do you get if you divide the
circumference of a bowl of ice cream
by its diameter?
A: Pi a'la mode.

25. Sources
http://www.pen.k12.va.us/Div/Winchester/jhhs/math/humor/pijokes.html
http://www.fourmilab.ch/gravitation/orbits/
http://www.math.nyu.edu/~crorres/Archimedes/contents.html
http://www.ifoce.com/records.php
http://www.joyofpi.com/pifacts.html
http://www.math.com/tables/constants/pi.htm
http://www.mathforum.com/library/drmath/view/57543.html
http://www.sixflags.com
http://www.worldslargestthings.com