\tan \theta = \frac{\sqrt{1 - \left(\frac{1}{3}\right)^2}}{\frac{1}{3}} = \frac{\sqrt{1 - \frac{1}{9}}}{\frac{1}{3}} = \frac{\sqrt{\frac{8}{9}}}{\frac{1}{3}} = \frac{\frac{2\sqrt{2}}{3}}{\frac{1}{3}} = 2\sqrt{2}