# @Pi (Formula Language)

Returns the constant value pi, accurate to fifteen decimal places. The value pi is the ratio of the circumference of a circle to its diameter.

@Pi

## Return value

pi

The number 3.14159265358979.

## Examples

1. This formula returns the circumference of a circle with a radius that equals 5.
``2 * @Pi * 5``
2. This formula converts an angle from degrees to radians. One degree equals pi/180 radians. Thus an angle of 360 degrees equals 2pi radians, 180 degrees equals pi radians, and so on.
``( angle * @Pi ) / 180``
3. Given the latitude of a particular location, you can find a location's distance from the equator. The numeric field latitude holds the latitude in degrees. The numeric field distance computes the distance from the equator using this formula.

First, latitude is converted to radians. Next, it's multiplied by 6440, the approximate radius of the earth in kilometers. This gives us the length of the arc from the equator to the given latitude.

Notes/Domino treats an empty numeric field as a text field, so the formula uses @If to check for an empty latitude field.

``@If( latitude = ""; 0; ( ( latitude * @Pi ) / 180 ) * 6440 )``