Combining the 4 semi-circles of the pool, we can make 2 circles, with a diameter of 10 yd.
The perimeter of a circle is calculated as follows:
[tex]P=\pi\cdot D[/tex]
where D is the diameter.
Then, the perimeter of the swimming pool is:
[tex]\begin{gathered} P=2\cdot\pi\cdot10 \\ P=62.8yd^{} \end{gathered}[/tex]
