Assume that you have a traveling wave of the form $y(x,t) = A \sin(kx - \omega t)$ with wave vector $k=1.5 \text{m}^{-1}$, which is depicted at time 1.5 s below. If you know the amplitude at the position $x=2.25$ m indicated by the cyan vertical line in the graph (the amplitude and the position in m are provided by the labels in the legend of the plot), what is the angular frequency of this wave? (Provide your result rad/s with two decimal places, but do not include the units.)