I am trying to find area of this polygon, image is attached.. Can anyone tell how to use polyarea function on this ?I have pasted the code

%%Aluminium
theta1=[88,89,90,91,92,94,96,94,90,89,-100,-102,-104,-105,-104,-102,-101,-100];
radius1=[5,7,11,17,26,39,46,44,32,3,0,18,34,32,33,29,28,20];
%subplot(211)
theta_rad=theta1*pi/180;
polar(theta_rad, radius1, 'b*');
hold on;
[x, y] = pol2cart(theta_rad, radius1);
k = convhull(x, y);
xch = x(k);
ych = y(k);
[thetaCH1, rhoCH1] = cart2pol(xch, ych);
%subplot(212)
polar(thetaCH1, rhoCH1, 'ro-');

Answer 1

[Walter Roberson]

polyarea cannot be used for that. polyarea assumes that each edge is linear, but the edges of a polar plot are mostly curved.