PostgreSQL/Math Functions/radians

radians(d): Returns radian equivalent to d degrees

postgres=# -- radians(d): Returns radian equivalent to d degrees
postgres=# SELECT radians(180) AS half_circle,
postgres-#        radians(360) AS full_circle;
   half_circle    |   full_circle
------------------+------------------
 3.14159265358979 | 6.28318530717959
(1 row)
postgres=#