Keyboard Access:'π' (when both flags -2 and -3 are clear) 3.14159265359 (when either flag -2 or -3 are set)HP-28: the key HP48S: LS-SPC HP48G: LS-SPC MTH NXT CONST HP49/50: LS-SPC LS-MTH NXT CONST « CONSTANTS »Pi constant function: Returns the symbolic constant or its numerical representation, 3.14159265359. is defined as the ratio of any circle’s circumference to its diameter. In simple English, the distance around any circle is exactly times the distance across it.
Since the radius of a circle is half its diameter, the circumference is radii (radiuses) in length, hence 360° = radians, as demonstrated by .
Another Fascinating Factoid: returns the first twenty four digits of , split between two stack levels.
Note that is recognized by some functions and is handled exactly.
Example (in Exact mode with flags -2 and -3 clear):