Solving normal vectors that are not of unit length

I have generated a triangulate mesh in Matlab through the triangulation and the trisurf function. I am trying to calculate the facenormal vectors from the centre of each triangulated mesh since that will provide me with the area of each mesh which i require. I have tried to produce 2 vectors from one point index to the other and cross multiplied them to get the normal vector however it does not seem to give me an accurate representation of the magnitude of the area of each mesh.

 % % FINDING AREA OF TRIANGLES           %%%%%%%%%FOR MAIN BODY%%%%%%%%%%
% % Defining the X Y Z coordinate

Vt1=k11(:,1); %first point index Vt2=k11(:,2); %second Vt3=k11(:,3); %third

% Vector 1

    for i = 1:length(Q11)    %Q11 is number of nodes in the mesh

        Vt4(i,:)=colibri15(Vt1(i),:);
        Vt5(i,:)=colibri15(Vt2(i),:); 

    end

    d12=[Vt5(:,1)-Vt4(:,1) Vt5(:,2)-Vt4(:,2) Vt5(:,3)-Vt4(:,3)];

% Vector 2

    for i = 1:length(Q11)

        Vt6(i,:)=colibri15(Vt1(i),:);
        Vt7(i,:)=colibri15(Vt3(i),:);

    end

    d13=[Vt7(:,1)-Vt6(:,1) Vt7(:,2)-Vt6(:,2) Vt7(:,3)-Vt6(:,3)];

colibri15 is the body that i generated the mesh around and stores the coordinates of the nodes.

Answer 1

[Steven Lord]

If you're using a triangulation object, consider using the faceNormal function on your triangulation.

[Huzaifa Iftikhar]

I have tried but returns vectors of unit length which is the problem.