Площадь и периметр шестиугольника

program laukums;
var a,b,c,d,e,f,g,h,i,k,l,s1,s2,s3,s4,s,SS,PP:real;
x1,x2,x3,x4,x5,x6,y1,y2,y3,y4,y5,y6:real;
 
procedure lauk(var a,b,c,s:real);
var p:real;
begin
p:=(a+b+c)/2;
s:=sqrt(p*(p-a)*(p-b)*(p-c));
end;
 
begin
writeln('ievadiet koordinatu parus');
readln(x1,y1,x2,y2,x3,y3,x4,y4,x5,y5,x6,y6);
c:=sqrt(sqr(x2-x1)+sqr(y2-y1));
d:=sqrt(sqr(x3-x1)+sqr(y3-y1));
e:=sqrt(sqr(x4-x1)+sqr(y4-y1));
f:=sqrt(sqr(x5-x1)+sqr(y5-y1));
g:=sqrt(sqr(x6-x1)+sqr(y6-y1));
h:=sqrt(sqr(x3-x2)+sqr(y3-y2));
i:=sqrt(sqr(x4-x3)+sqr(y4-y3));
k:=sqrt(sqr(x5-x4)+sqr(y5-y4));
l:=sqrt(sqr(x6-x5)+sqr(y6-y5));
 
 
lauk (c,d,l,s1);
lauk (k,l,e,s2);
lauk (f,i,k,s3);
lauk (h,i,g,s4);
 
SS:=(s1+s2+s3+s4);
writeln('laukums ir',SS);
PP:=(c+d+e+f+g+h);
writeln('perimetrs ir',PP);
readln
end.

program laukums;
uses crt;
var a,b,c,d,e,f,g,h,i,k,l,s1,s2,s3,s4,s,SS,PP:real;
x1,x2,x3,x4,x5,x6,y1,y2,y3,y4,y5,y6:real;
 
procedure lauk(var a,b,c,s:real);
var p:real;
begin
p:=(a+b+c)/2;
s:=sqrt(p*(p-a)*(p-b)*(p-c));
end;
 
begin
clrscr;
writeln('ievadiet koordinatu parus');
readln(x1,y1,x2,y2,x3,y3,x4,y4,x5,y5,x6,y6);
c:=sqrt(sqr(x1-x2)+sqr(y1-y2));
d:=sqrt(sqr(x1-x3)+sqr(y1-y3));
e:=sqrt(sqr(x2-x3)+sqr(y2-y3));
 
f:=sqrt(sqr(x1-x4)+sqr(y1-y4));
g:=sqrt(sqr(x3-x4)+sqr(y3-y4));
 
h:=sqrt(sqr(x1-x5)+sqr(y1-y5));
i:=sqrt(sqr(x4-x5)+sqr(y4-y5));
k:=sqrt(sqr(x1-x6)+sqr(y1-y6));
l:=sqrt(sqr(x5-x6)+sqr(y5-y6));
lauk (c,d,e,s1);
lauk (d,f,g,s2);
lauk (f,h,i,s3);
lauk (h,k,l,s4);
SS:=(s1+s2+s3+s4);
writeln('laukums ir',SS:0:2);
PP:=(c+i+e+k+g+h);
writeln('perimetrs ir',PP:0:2);
readln
end.