#### Answer

The distance between these two points is 2.5 meters.

#### Work Step by Step

We can find the wavelength of the wave as:
$\lambda = \frac{v}{f}$
$\lambda = \frac{340~m/s}{120~Hz}$
$\lambda = 2.83~m$
We can find the distance $\Delta x$ between the two points as:
$\lambda = \frac{2\pi~\Delta x}{\Delta \phi}$
$\Delta x = \frac{\lambda ~\Delta \phi}{2\pi}$
$\Delta x = \frac{(2.83~m)~(5.5~rad)}{2\pi}$
$\Delta x = 2.5~m$
The distance between these two points is 2.5 meters.