To perform the calculations for the circumference and area of a circle, you may have used the π key on your calculator. When you press this key, the screen of your calculator shows more digits than the 3.14 you use as an approximation for pi.

2 answers

What is the exact value of pi?

The exact value of pi is 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679.
Actually it goes on forever. There is no exact value for this irrational quantity.