Rotational Motion

The position vector of 1 kg object is \(\overrightarrow r = \left( {3\widehat i - \widehat j} \right)m\) and its velocity \(\overrightarrow v = \left( {3\widehat j + \widehat k} \right)m{s^{ - 1}}\). The magnitude of its angular momentum is \(\sqrt x\) Nm where x is ___________.