Answer:
a.

b.

c.

Explanation:
The formula to find the circumference of a circle is:

Where "r" is the radius of the circle.
In this case you can identify that:

Then:
a. Substituting the radius of the circle into the formula, you get:

b. Substitute the radius into the formula (Remeber to use
) and then evaluate. So you get:

c. Substitute the radius into the formula but this time you must use the π button in the calculator:

Rounded to the nearest hundreth, this is:
