RADIANS(a)

RADIANS() converts the angle in degrees to angle in radians.

Description

One radian is the angle subtended at the center of a circle by an arc that is equal in length to the radius of the circle.
The radian is represented by symbol rad.
Formula for converting from degrees to radians is :

Angle in radians = angle in degrees x Failed to parse (syntax error): {\displaystyle \frac{\pi}{180 °}}

If argument $a$ is non-numeric, Calci returns a NaN error.
RADIANS() can be used for array of angles e.g. 0 to 90 degress in steps of 15 degrees as -

RADIANS(0..90..15)