euler_problem_9.php

function euler_9($n) {
    $a = $b = $c = 1;
    for ($a = 1;$a <= $n-2;$a++) {
        for ($b = 1; $b <= $n-1-$a;$b++) {
            $c = $n - $a - $b;
            if (pythag_trip($a,$b,$c)) {
                return $a . ', ' . $b . ' and ' . $c . ' make ' . $a*$b*$c . '.';
            }
        }
    }
}

function pythag_trip($a,$b,$c) {
    if ($a**2 + $b**2 == $c**2 || $a**2 + $c**2 == $b**2 || $b**2 + $c**2 == $a**2) {
        return true;
    }
}

echo euler_9(1000); // Returns "200, 375 and 425 make 31875000."