Point::aireTriangle PHP Метод

    static function aireTriangle($pointA, $pointB, $pointC)
    {
        $AB = Point::distance($pointA, $pointB);
        $BC = Point::distance($pointB, $pointC);
        $AC = Point::distance($pointC, $pointA);
        return sqrt(($AB + $BC + $AC) * (-$AB + $BC + $AC) * ($AB - $BC + $AC) * ($AB + $BC - $AC)) / 4;
    }