suppose z1, z2, z3 represently the vertices A, B, and C respectively of a ∆ABC with centroid at G. If the mid point of AG is the origin, then,
z1+z2+z3=0
2z1+z2+z3=0
z1+z2+4z3=0
4z1+z2+z3=0
Affix of G is 13z1+z2+z3
As origin is the mid-point of AG,
0=1213z1+z2+z3+z1⇒4z1+z2+z3=0