Answer
$309$ meters
Work Step by Step
The wave must travel to the cliff and back. Therefore, $\Delta x=2d$, where d is the distance from the shouter to the cliff. Using the fact that $v=\frac{\Delta x}{\Delta t}$, $$\Delta x=2d=v\Delta t$$ Solving for $d$ yields $$d=\frac{v\Delta t}{2}$$Substituting known values of $v=343m/s$ and $\Delta t=1.80s$ yields a distance of $$d=\frac{(343m/s)(1.80s)}{2}=309m$$
