Home 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. Invention of zero Interesting facts on zero Uses of Pi Easy trick no.1 Easy trick no.2 More examples Our Team Source: www.4to40.com/science/index.asp?id=100 http://en.wikipedia.org/wiki/pi http://ualr.edu/lasmoller/pi.html Bharathi Bhawan mathematics for class 6 by RS Aggarwal