Answer
You would be walking $259.4$ yd.
Work Step by Step
We can use the law of sines to relate the two angles and their opposite sides to one another:
$\frac{sin 54^{\circ}}{210} = \frac{sin 88^{\circ}}{x}$
Multiply each side by $x$:
$\frac{sin 54^{\circ}}{210}(x)$ = sin $88^{\circ}$
Divide each side of the equation by $\frac{sin 54^{\circ}}{210}$ to solve for $x$:
$x \approx 259.4$ yd.
You would be walking $259.4$ yd.