product1896.php

<?php

if ($diagonal < $diag_min) {
    $diagonal = $diag_min;
    if ($changed == "width") {
        $height = sqrt(pow($diagonal, 2) - pow($width, 2));
    }
    if ($changed == "height") {
        $width = sqrt(pow($diagonal, 2) - pow($height, 2));
    }
}

if ($diagonal > $diag_max) {
    $diagonal = $diag_max;
    if ($changed == "width") {
        $height = sqrt(pow($diagonal, 2) - pow($width, 2));
    }
    if ($changed == "height") {
        $width = sqrt(pow($diagonal, 2) - pow($height, 2));
    }
}