Issue with for loop with different size of matrixes

Hello,

I'm trying to add the neighbor triangles in delaunay triangulation. For some reason I am having issue with the size of the two matrices. Can you please help me?

v = neighbors(DT);
v(1,:)
for i = 1:size(v,2)
    if isnan(v(1,i)) == 0
       
   x21(i) = [DT.Points(DT.ConnectivityList(v(1,i),1),:),0]; 
   area2(i) = 1/2.*abs((x21(2,1)-x21(1,1)).*(x21(3,2)-x21(1,2))-(x21(3,1)-x21(1,1)).*(x21(2,2)-x21(1,2)));
    end
    
end