public function aspectRatio($slideNumber)
    {
        if ($slideNumber == '')
            throw new Exception('Slide number not specified');

        //build URI
        $strURI = Product::$baseProductUri . '/slides/' . $this->getFileName() . '/slides/' . $slideNumber;

        //sign URI
        $signedURI = Utils::sign($strURI);

        $response = Utils::processCommand($signedURI, 'GET', '', '');

        $json = json_decode($response);
        
        if ($json->Code == 200)
            return $json->Slide->Width / $json->Slide->Height;
        else
            return false;
    }