The length of a rectangular swimming pool = 50 yards
The width of a rectangular swimming pool = 20 yards
We can use the Pythagoras theorem to find the length of the diagonal.
![\begin{gathered} c^2=a^2+b^2 \\ c^2=50^2+20^2 \\ c^2=2500+400 \\ c^2=2900 \\ c=\sqrt[]{2900} \\ c=53.85\: \text{yards} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/ykp8jjas87xm18941ut1xd8lk1px9cf12v.png)
Therefore, the approximate length of the diagonal of this pool is 53.85 yards.
Option (A) is correct.