The polaroids $P_1,P_2\&P_3$  arranged coaxially. The angle between $P_{1}and{P}_2$ is  $37°$. If intensity of emerging light is one quarter of intensity of unpolarized light, the angle $P_{2}and{P}_3$  is,  $\theta ={\cos }^{-1}\left(\frac{x}{4\sqrt{2}}\right)$ 
,then $x$ is________ ?