Pi values

1. Jul 28, 2004

miguel314

My dad and I got in an argument about accuracy of pi values. He said that the ratio 22/7 will always be more accurate than any decimal value of pi. I said that the value 3.14159265358979 is much more accurate. I'm 100% certain that I am correct, but I can't really think of how to prove this to him. I'd also like to know how those values are measured, exactly. Thank you for your time.

2. Jul 28, 2004

chroot

Staff Emeritus
22/7 is an approximation to pi. It's not even accurate to three digits.

- Warren

3. Jul 28, 2004

chroot

Staff Emeritus
4. Jul 28, 2004

HallsofIvy

22/7= 3.142857143. As chroot said, not even to three digits.

(It is, however, the best approximate fraction with no more than 2 digits in the numerator.)

5. Jul 28, 2004

Zorodius

To actually answer your question, you are looking for a proof of the irrationality of Pi. One such proof is http://www.lrz-muenchen.de/~hr/numb/pi-irr.html [Broken] Google for "irrational pi proof" to see more.

Of course, in this context, the best "proof" would probably be to show him a calculator, press the Pi key, and then enter 22/7 for contrast.

Last edited by a moderator: May 1, 2017
6. Jul 28, 2004

miguel314

thanks for the help, all...

7. Aug 2, 2004