How did pi get its name?

Answer 1

'pi' is the small Classical Greek letter 'p'. It means proportion.

Rememer the circle equation

C = pi d

Circumfenrence equal 'pi; multiplied to the diamter.

'pi' is the constant of proportion

From Classical times it was found, that however big or small a circles circumference and it related diameter, the constant of proportionality (pi) was always the same at 3.141592..... (Trailing dots indicate , 'to infinity').

pi is an IRRATIONAL Number, which casually means that the decimals go to inifinuty and there is no regular order in the decimal digits. It cannot be converted to an EXACT ratio(fraction).

Values such as, 3.14, 3.1416, 3.141592. 22/7 are only approximations for 'pi'. The more decimal digits , the more exact the value of 'pi' , but it is still an approximation.

Answer 2

The word "Pi" derives from the letter "P" (π) out of the Greek alphabet, which is the first letter of the word "περιφέρεια" - peripheria meaning periphery, respectively "περίμετρος" - perimetros, Greek for circumference.

It is named for the Greek letter Pi , which is the first letter of the Greek word for circumference.