The area of a circle:
[tex]2\pi \: {r}[/tex]
We need to first find the radius of the circle:
4÷2
=2
We can then find the circumference:
[tex]2\pi(2) \\ = 4\pi \\ = 12.566...[/tex]
If you are to take absolute value,the answer would be 4兀m.
Otherwise,the aswer would be 12.566m.
Hope it helps!