Equation for the centroid a semi circular arc is x=2*r/(pi). If I have a circle with 1 cm of radius then its centroid is 2r/(pi)= 0.637 cm. Now I use the equation of this circle x^2+y^2=1^2 in Matlab to find all x coordinates of the circle. Then I find the mean of the all x coordinates, which is equal to 0.7812 cm.
According to definition of centroid: "Centroid is the mean position of all the points in all of the coordinate directions". Why does calculated mean value of x coordinates is not same as the value of centroid calculated by equation "x=2*r/(pi)" ?.
Here is the MATLAB code:
x= sqrt( 1-y.^2);
Link for the equation: https://mathworld.wolfram.com/PappussCentroidTheorem.html