We are given:
$\sin \theta = \frac{1}{9}$
Using the identity:
$\sin \theta = \frac{\text{opposite}}{\text{hypotenuse}}$
Let the opposite side be $1$ and the hypotenuse be $9$.
Using the Pythagorean theorem:
$\text{hypotenuse}^2 = \text{opposite}^2 + \text{adjacent}^2$
$9^2 = 1^2 + \text{adjacent}^2$
$81 = 1 + \text{adjacent}^2$
$\text{adjacent}^2 = 80$
$\text{adjacent} = \sqrt{80} = 4\sqrt{5}$
Now,
$\tan \theta = \frac{\text{opposite}}{\text{adjacent}} = \frac{1}{4\sqrt{5}}$