**Curved Line:** In general, the centroid
of a curved line is not located on the line itself but at some
distance away. In this case, integral equations are used to
determine the position of the centroid as

(2) |

where dl is the differential line segment (element), and x y z are the centroidal coordinates ("moment arms") of the differential element. In this case also we are free to choose any coordinate system that simplifies the integrations in Eq. (2).