Interesting Math History 


Question : 
How do you explain pi (p) in a simple way ? 
Answer : 
Many
practical problems are concerned with the measurements of a
circle. And the basic to the measurements is the fact that the
ratio of the circumference to its diameter is a constant. No
matter what the size of the circle the ratio remains the same.

In mathematics, this ratio is represented by the Greek letter
p (pi). 
However this constant is not an integer and much effort has been spent to find the value of this ratio. It has been evaluated
to a large number of decimal points by electronic calculators.
The story of the accuracy to which the value of p is known is an interesting one.
In the Bible, the value of p is used as 3 Archimedes had declared the value of p as less than 3 1/7 but greater than
3 10/71. The value generally used today 3.1416 was known at the time of Ptolemy (A.D. 150).
In 1949, with the use of the Computer Eniac, a group of mathematicians calculated 2037 decimals of p in 70 hours.
And recently Daniel Shanks and John Wrench have published p to 100,000 decimals. It took them 8 hours and 43 minuts on an IBM
7090 system to compute this result.
However for practical use the approximation of p 3.1416 is sufficient.

