Pi is ROUNDED to 3.14. Pi really goes on for ever and ever.

Good question. I have found PI/4 useful in calculating the cross sectional area of a circle.

PI/4= 0.785398163397448

If a circle has a diameter of .5 inches, the follow this formula to get its cross sectional area:

Diameter squared X 0.7854 = CSA

Or,

0.196349540849362 Square Inches

PI/4= 0.785398163397448

If a circle has a diameter of .5 inches, the follow this formula to get its cross sectional area:

Diameter squared X 0.7854 = CSA

Or,

0.196349540849362 Square Inches