Why does this PHP function return the wrong result?

Question

I wrote a user function to return the distance between two points on an x,y coordinate system. The input params were 0,0,10,10.

Here is the original code:

public static function dist2d($x1,$y1,$x2,$y2) {
   return sqrt((($x2 - $x1) * ($x2 - $x1)) + (($y2 - $y1) * ($y2 - $y1)));
}

This returns 110.

Here is the code that works:

public static function dist2d($x1,$y1,$x2,$y2) {
    $result = (($x2 - $x1) * ($x2 - $x1)) + (($y2 - $y1) * ($y2 - $y1));
    return sqrt($result);
}

This returns 14.1.

I am new to PHP, what is going on here?

Answer 1

Both of these functions return 14.142135623731.