program plotaj;
 uses crt;
 
 procedure staciakampis (a, b : real; var P : real);
 begin
  P:= a * b;
end;

 procedure trikampis (c, h : real; var S : real);
 begin
  S:= 0.5 * c * h
 end;
 
 function trapecija (q, w, u : real) : real;
 begin
 trapecija:= ((q + w) / 2) * u;
 end;
 
 function rombas (t, r : real) : real;
 begin
 rombas:= (t * r) / 2;
 end;
 
 procedure langas (x1, y1, x2, y2, sp : integer);
 begin
   window (x1, y1, x2, y2);
   textbackground(sp); clrscr
  end;
  
var a, b, P, c, h, S, q, w, u, t, r : real;

begin
 langas(2, 2, 30, 5, 2);
 writeln ('A, tu Gyrdi Yvesk staciakampio krashtiniu');
 read (a, b);
 staciakampis (a, b, P);
 langas(2, 7, 30, 9, 5);
 writeln ('ploc:' ,P);
 writeln ('o dabar trikampio krashtine ir aukstine');
 read (c, h);
 trikampis (c, h, S);
 writeln ('plotynas:' ,S);
 writeln('metas ivesti trapecijos pagrindus ir aukstine');
 trapecija (q, w, u);
 writeln('stai ploto jums prasom' ,trapecija:5:2);
 writeln('ivesk rombo istrizaines');
 read(t, r, O);
 writeln('skanukoo?' ,O);
 Readln;
 readln;
end.