What is the formula for center of gravity fo traingle?

Answer 1

First I assume that you mean triangle and not traingle. The answer depends on the form in which you have information about the triangle.

If the vertices of the triangle are known in terms of their coordinates: if the three vertices are (xa, ya), (xb, yb) and (xc, yc) then the CoG has the coordinates [(xa+xb+xc)/3, (ya+yb+yc)/3)].

Otherwise, they CoG is the point where the medians of the triangle meet.