the center of gravity of a triangle is the intersection point of the center lines of the three sides of the triangle. when the geometry is a homogeneous object, the center of gravity coincides with the centroid.

in the plane rectangular coordinate system, the coordinate of the center of gravity is the arithmetic mean of the vertex coordinates,

that is, its coordinates are ((x1+x2+x3)/3, (y1+y2+y3)/3;

spatial rectangular coordinate system - abscissa: (x1+x2+x3)/3, ordinate: (y1+y2+y3)/3, vertical coordinate: (z1+z2+z3)/3