Найти площадь трех треугольников

uses crt;
{$R+}
var x1,x2,x3,y1,y2,y3,x11,x22,x33,
y11,y22,y33,x111,x222,x333,y111,y222,y333:integer;
p,ab,bc,ac,piv,s,p1,p2,s1,s2,piv1,piv2,ab1,bc1,ac1,
ab2,bc2,ac2:comp;
 
procedure dlina (var dl:comp;x,xx,y,yy:integer );
begin
dl:=(sqrt(sqr(x-xx)+sqr(y-yy)));
end;
 
function perimetr (a,b,c:comp):comp;
begin
perimetr:=a+b+c;
end;
 
 begin
clrscr;
writeln('vvedite koordinati 1 triugolnika x1,x2,x3,y1,y2,y3 -> ');
read(x1,x2,x3,y1,y2,y3);
writeln('vvedite koordinati 2 triugolnika x1,x2,x3,y1,y2,y3 -> ');
read(x11,x22,x33,y11,y22,y33);
writeln('vvedite koordinati 3 triugolnika x1,x2,x3,y1,y2,y3 -> ');
read(x111,x222,x333,y111,y222,y333);
dlina(ab,x2,x1,y2,y1);
dlina(bc,x3,x2,y3,y2);
dlina(ac,x3,x1,y3,y1);
dlina(ab1,x22,x11,y22,y11);
dlina(bc1,x33,x22,y33,y22);
dlina(ac1,x33,x11,y33,y11);
dlina(ab2,x222,x111,y222,y111);
dlina(bc2,x333,x222,y333,y222);
dlina(ac2,x333,x111,y333,y111);
p:=perimetr(ab,bc,ac);
p1:=perimetr(ab1,bc2,ac2);
p2:=perimetr(ab2,bc2,ac2);
piv:=p/3;
writeln(piv:3:2);
piv1:=p1/3; piv2:=p2/3;
s:=sqrt(piv*(piv-ab)*(piv-bc)*(piv-ac));
s1:=sqrt(piv1*(piv1-ab1)*(piv1-bc1)*(piv1-ac1));
s2:=sqrt(piv2*(piv2-ab2)*(piv2-bc2)*(piv2-ac2));
 
writeln('s 1 triugolnika = ',s:3:2);
writeln('s 2 triugolnika = ',s1:3:2);
writeln('s 3 triugolnika = ',s2:3:2);
 
readkey;
end.