To determine which of the provided expressions are rational, let's evaluate each one:
-
\( \sqrt{3} + \sqrt{3} \)
This simplifies to \( 2\sqrt{3} \). Since \( \sqrt{3} \) is irrational, \( 2\sqrt{3} \) is also irrational. -
\( \sqrt{3} \times \sqrt{3} \)
This simplifies to \( 3 \). This is a rational number. -
\( \frac{1}{\sqrt{3}} \)
This is an expression where the denominator is an irrational number, thus \( \frac{1}{\sqrt{3}} \) is irrational. -
\( \frac{\sqrt{3}}{1} \)
This simplifies to \( \sqrt{3} \), which is irrational.
From the analysis above, the only rational expression among the options is:
\( \sqrt{3} \times \sqrt{3} = 3 \).