The Number pi
pi is a mathematical constant, whose value is the ratio between the circumference
of any circle to its diameter. pi can also be defined as the ratio between the area of
any circle to the square of its radius.
In 1706, a famous English mathematician, William Jones, introduced the symbol
for pi, which was TT. In 1737, Euler adopted this symbol and it became the
standard symbol for pi.
The value of TT is approximately equal to 3.14159.
The value of TT cannot be expressed exactly as a fraction a/b, where a and b are
integers. So, TT is an irrational number. Also, its decimal representation never
ends. Throughout the history of mathematics, scientists have been putting lot of
effort to find the value of TT more accurately and to understand its nature.
Bharathi Bhawan mathematics for class 6 by RS Aggarwal