function leng(x1, y1, x2, y2 : integer) : real;
begin
     leng :=  sqrt(sqr(y1 - y2) + sqr(x1 - x2));
end;
 
function checkTria (x1, y1, x2, y2, x3, y3: integer) : boolean;
var
   ab, bc, ac : real;
begin
     ab := leng(x1, y1, x2, y2);
     bc := leng(x2, y2, x3, y3);
     ac := leng(x1, y1, x3, y3);
     checkTria := ((ab + bc - ac) > 0) and ((ab + ac - bc) > 0) and ((bc + ac - ab) > 0);
  end;
 
var
   x1, x2, x3, y1, y2, y3, a, b, c ,d, e ,f, g : integer;
   xc, yc, r : real;
 
begin
     Write('Введите 3 координаты: ');
     Readln(x1, y1, x2, y2, x3, y3);
 
     if not(checkTria(x1, y1, x2, y2, x3, y3)) then Writeln('Такого треугольника не существует')
     else
     begin
 
 
A := x2 - x1;
B := y2 - y1;
C := x3 - x1;
D := y3 - y1;
E := A * (x1 + x2) + B * (y1 + y2);
F := C * (x1 + x3) + D * (y1 + y3);
G := 2 * (A * (y3 - y2) - B * (x3 - x2));
if G = 0 then Exit;
xc := (D * E - B * F) / G;
yc := (A * F - C * E) / G;
              r := (sqrt(sqr(x1 - xc) + sqr(y1 - yc)));
 
           Writeln('Центр окружности: ', xc:0:2, ', ', yc:0:2);
           Writeln('Радиус: ', r:0:2);
     end;
     Readln;
end.