Answer:
10[tex]\pi[/tex] meters.
Step-by-step explanation:
We know that to calculate the circumference of a circle, you must use the formula C=d[tex]\pi[/tex].
Since he swam half-way around the island, we will need to take half of our final answer.
To solve, you can begin substituting in the diameter by:
C=20[tex]\pi[/tex]
Now, take half of this answer.
[tex]\frac{C}{2}[/tex]=10[tex]\pi[/tex].
