2. What Is Pi?
• Equal to the number of times a circle’s
diameter will fit around the circle
• Approximately 3.14
• Pi goes on for ever
• Decimals have no pattern and don’t repeat
• Pi is an irrational number
3. History of Pi – Early attempts
• 1650 BC – Rhind Papyrus
Value of 3.16 probably found by
measurement
• Bible – 1 Kings 7:23
Value of 3 (not very accurate)
• Archimedes (287 – 212 BC)
Calculated between 223
/71 and 22
/7
4. History of Pi – AD (CE)
• Tsu Ch’ung Chi (430
– 501 AD)
355
/113
• Brahmagupta (640)
Value of pi =
= 3,1622
• Al-Kashi (1430
Calculated pi to 14
decimal places
• Newton (1665)
Calculated pi to 16
decimal places
• Ferguson (1946)
Calculated pi to 620
decimal places
10
5. History of Pi - Computers
• Ferguson (1947)
Calculated to 710 places using a desk
calulator
• Kanada & Takashi (Sept 1999)
Used a computer to calculate pi to
206,158,430,000 decimal places
6. Pi and Different Cultures
• Earliest discoveries (BCE) and
investigations made by Egyptians and
Greek mathematicians
• Between 230 AD and 1430 AD further
investigation carried out by Chinese, Indian
and Arabic mathematicians - why?
• More recent discoveries made by Western
and Japanese mathematicians
7. Why is Pi so Fascinating?
• Provides an intellectual challenge
• Because it exists
• Lead to important discoveries in modern
mathematics
• Can be calculated using sequences of
rational numbers
• Lead to developments in computer
technology