#### Answer

$\frac{\sqrt 21}{3}$

#### Work Step by Step

Step 1: $\sqrt \frac{7}{3}$
Step 2: $\frac{\sqrt 7}{\sqrt 3}$
Step 3: To rationalize the denominator, we multiply the numerator and
denominator by a factor that makes the radicand in the denominator a perfect square.
Step 4: $\frac{\sqrt 7\times\sqrt 3}{\sqrt 3\times\sqrt 3}$
Step 5: $\frac{\sqrt 21}{3}$