It’s Pi Day! Do you have any special Pi Day activities planned to celebrate this mathematical holiday?
You might want to consider sharing a brief history of pi with your children. Pi has a long history which dates back to over a millennium before Christ. Persons from all over the globe have worked at calculating this irrational number. While it has taken modern computers to push the limits on determining the greatest number of digits in pi, the works of ancient mathematicians like Archimedes pictured here provided the foundation.
If you’d like to know more about what Archimedes did as well as the ten trillionth digit of pi, keep reading.
A History of Pi
The first time that we see pi in recorded history is with the Babylonians. They estimated pi to be 25/8 or 3.125 as was discovered on a clay tablet which dates back to around 1900-1680 BC.
The ancient Egyptians were less than 1% off in their calculation of pi. The scribe Ahmes wrote in the Rhind Papyrus, “Cut off 1/9 of a diameter and construct a square upon the remainder; this has the same area as the circle.” Using his estimation, pi would be about 3.1605.
The ratio of pi is mentioned in the Bible in 1 Kings 7:23. It says, “Now he made the sea of cast metal ten cubits from brim to brim, circular in form, and its height was five cubits, and thirty cubits in circumference.” This is referring to a pool that was made for the Temple which Solomon built.
The first calculation of pi was done in ancient Greece by the famous mathematician Archimedes. He found the area of a polygon that was inscribed within a circle. Then he found the area of a polygon within which the same circle was circumscribed. This provided him with the upper and lower bounds for the area of the circle. With 96-sided polygons, he calculated pi to be 3.1485.
Two mathematicians in ancient China are credited with finding more precise values of pi. Around 265 AD, Liu Hui used a 3,072-sided polygon to determine a value of 3.1416. Later, Zu Chongzhi used Liu Hui’s algorithm with a 12,288-sided polygon to obtain a value of 355/113 which is 3.141592920353982.
An astronomer-mathematician from India by the name of Aryabhata figured pi around the year 499 AD. He wrote, “Add four to 100, multiply by eight, and then add 62,000. By this rule the circumference of a circle with a diameter of 20,000 can be approached.” This turns out to be 3.1416.
The well-known, Italian mathematician of the Middle Ages, Fibonacci, used a polygon method to arrive at a number of 3.1418 for pi around the year 1200 AD.
The Greek letter ∏ was first associated with this ratio in the year 1706. William Jones, a math teacher from Wales, used the symbol in his book Synopsis Palmariorum Matheseos. Prior to that time, pi was referred to as “quantitas in quam cum multiflicetur diameter, proveniet circumferencia” which is Latin for “the quantity which, when the diameter is multiplied by it, yields the circumference.” The symbol ∏, incidentally, is the first letter in the Greek word for “perimeter.”
The Swiss mathematician,Leonard Euler made the use of the symbol ∏ popular in 1737.
In modern times, computers have made it easier to determine pi. In the year 2011, Shigeru Kondo, using Alexander Yee’s software and a home computer with multiple hard drives, calculated pi to ten trillion digits. It took 371 days due to multiple failures. The ten trillionth digit, by the way, is 5.
Others have contemplated pi over the ages. This is just a brief account of major contributors to the history of pi.
I hope you and your children have a great day celebrating pi. I would love to hear about the activities you do in the comment section below.
Many blessings,