Get distance between 2 points

function getDistanceBetweenPoints($latitude1, $longitude1, $latitude2, $longitude2) {
    $theta = $longitude1 - $longitude2;
    $distance = (sin(deg2rad($latitude1)) * sin(deg2rad($latitude2))) +
                (cos(deg2rad($latitude1)) * cos(deg2rad($latitude2)) *
                cos(deg2rad($theta)));
    $distance = acos($distance);
    $distance = rad2deg($distance);
    $distance = ($distance * 69.09) * 1.609344;
 
    return (round($distance,2));
}