How to perform calculations on points found with inpolygon?

Here is my code which is attempting to find the center of gravity by checking on the number of points with a particular polygon. Is there a way to add the values of these points within each polygon in addition to simply determining how many points there are?

while b-a > stop
r = b-a;
t = theta*r;
lam = a + t;
rho = b - t;
% Set the y-axis corners for polygon specification
c = jj;
d = jj+intj;
% Set the polygons:
xA = [a,a,lam,lam];
yA = [c,d,d,c];
xB = [lam,lam,rho,rho];
yB = [c,d,d,c];
xC = [rho,rho,b,b];
yC = [c,d,d,c];
% Use inpolygon to grab the number of points in each of the polygons
inA = inpolygon(RPM,BMEP,xA,yA);
inB = inpolygon(RPM,BMEP,xB,yB);
inC = inpolygon(RPM,BMEP,xC,yC);
% Determine the number of points in each polygon
x = numel(RPM(inA));
y = numel(RPM(inB));
z = numel(RPM(inC));
if x < z
    a = lam;
else
    b = rho;
end
end