function p =  perim(xvals,yvals)

x1=[xvals xvals(1)];    %Form augmented vector
y1=[yvals yvals(1)];

xd=diff(x1);        %Calculate differences
yd=diff(y1);

sqrd = xd.^2+yd.^2; %Square them
sqrtSqd=sqrt(sqrd); %Find distances

p=sum(sqrtSqd);     %Find perimeter