Answer :
pi is the ratio of the diameter to the circumference
circumference/diameter=pi
that's why c=pid or c=2pir
some digits are 3.14159265358979323846264338327950288419716939
937510582097494...
circumference/diameter=pi
that's why c=pid or c=2pir
some digits are 3.14159265358979323846264338327950288419716939
937510582097494...