[ART]

Код:

function Dist(p1, p2: TPoint): real;
begin
 Result := sqrt(sqr(p1.x - p2.x) + (p1.y - p2.y));
end;

function Geron(p1, p2, p3: TPoint): real;
var
 a, b, c: real;
 p: real;
begin
 a := Dist(p1, p2);
 b := Dist(p2, p3);
 c := Dist(p3, p1);
 p := (a + b + c) / 2;
 Result := sqrt(p * (p - a) * (p - b) * (p - c));
end;