Express $\frac{81}{64}\times 160$ as a single fraction.
$$\sqrt{\frac{81\times 160}{64}}$$
Multiply $81$ and $160$ to get $12960$.
$$\sqrt{\frac{12960}{64}}$$
Reduce the fraction $\frac{12960}{64}$ to lowest terms by extracting and canceling out $32$.
$$\sqrt{\frac{405}{2}}$$
Rewrite the square root of the division $\sqrt{\frac{405}{2}}$ as the division of square roots $\frac{\sqrt{405}}{\sqrt{2}}$.
$$\frac{\sqrt{405}}{\sqrt{2}}$$
Factor $405=9^{2}\times 5$. Rewrite the square root of the product $\sqrt{9^{2}\times 5}$ as the product of square roots $\sqrt{9^{2}}\sqrt{5}$. Take the square root of $9^{2}$.
$$\frac{9\sqrt{5}}{\sqrt{2}}$$
Rationalize the denominator of $\frac{9\sqrt{5}}{\sqrt{2}}$ by multiplying numerator and denominator by $\sqrt{2}$.
