Remember that the formula for the circumference, [tex]C[/tex], of a circle is:
[tex]C = d \pi[/tex]
In this case, we are not given the diameter. However, remember that the diameter is equivalent to two times the radius of a circle. Thus,
[tex]d = 2 \cdot 8 = 16[/tex],
and we can say the circumference of our circle is:
[tex]C = 16 \cdot 3.14 = 50.24 \,\textrm{units}[/tex]
The circumference of our circle is 50.24 units.
Also, a little side note not relating to the question:
Remember that [tex]\pi[/tex] is spelled as "pi" not "pie." Pie is a dessert, while pi is a mathematical constant.
