Express $\frac{\frac{1}{2}}{2}$ as a single fraction.
$$138\sqrt{\frac{1}{2\times 2}}$$
Multiply $2$ and $2$ to get $4$.
$$138\sqrt{\frac{1}{4}}$$
Rewrite the square root of the division $\frac{1}{4}$ as the division of square roots $\frac{\sqrt{1}}{\sqrt{4}}$. Take the square root of both numerator and denominator.
$$138\times \frac{1}{2}$$
Multiply $138$ and $\frac{1}{2}$ to get $\frac{138}{2}$.
