Tharindu,
First, it is Centroid, not Centeroid.
For a triangle, calculate the slope of two sides using SLOPE, the midpoints
using AVERAGE, take the negative inverses of the slopes and use those and
the midpoints to find the equation of the perpendicular bisector lines.
Then set those two equations for y equal and calculate the x intercept.
Then calculate y from one (or both, since they must be equal) equation, and
you have the centroid. The formulas are fairly complex because you need to
take into account infinite and 0 slope lines, and the errors that those
generate.
I have a worksheet that shows the centroid, the equation of the
circumscribing circle, and a graph which I will send to you if you contact
me privately.
HTH,
Bernie
MS Excel MVP
