Answer
$6\sqrt{5}\text{ miles}=13.4\text{ miles}$
Work Step by Step
Substitute $120$ for $h$ in the provided formula and calculate $d$.
That is.,
$\begin{align}
& d=\sqrt{\frac{3h}{2}} \\
& =\sqrt{\frac{3\times 120}{2}} \\
& =\sqrt{180}
\end{align}$
Write $180$ into its prime factors and take square root.
That is.,
$\begin{align}
& d=\sqrt{180} \\
& =\sqrt{{{2}^{2}}\cdot {{3}^{2}}\cdot 5} \\
& =\left( 2\cdot 3 \right)\sqrt{5} \\
& =6\sqrt{5}
\end{align}$
Now, use calculator to find the values in decimal.
So,
$\begin{align}
& 6\sqrt{5}=13.41 \\
& \simeq 13.4
\end{align}$
Thus, the distance that can be seen is $6\sqrt{5}\text{ miles}=13.4\text{ miles}$
