I have always believed that the fraction of Pi was 22/7.

The decimal value of 22/7 is equal to 3.142857143 to nine decimal points.

However now I find that the value of Pi on my Scientific Calculator is equal to

3.141592654 to nine decimal points.

Can anyone here explain the difference between these two numbers.?

For the last 79 years all my circumferences and areas of circles have been miscalculated.