"The Circumference of Sauron's Eye"

In the land of Mordor, where the shadows lie, there stood a great tower, and atop that tower, there was a single eye that gazed out upon the land. This eye belonged to Sauron, the Dark Lord, and it was said that he could see all that transpired in his realm.

Now, imagine that this eye was not just a single point, but a perfect circle. To find the circumference of this circle, one must first measure the distance around it. This can be done by taking a piece of string and wrapping it around the circle, marking where it meets the starting point.

Next, one must measure the length of the string that was used to wrap around the circle. This length is the circumference of the circle, and it can be calculated using the formula C = 2πr, where C is the circumference, π is the mathematical constant pi, and r is the radius of the circle.

In the case of Sauron's eye, the radius would be the distance from the center of the eye to its edge. Once this distance is known, the circumference can be calculated using the formula above.

But beware, for Sauron's eye is not to be trifled with. Those who seek to measure its circumference may draw the attention of the Dark Lord himself, and suffer dire consequences.

Prompt

Explain how to get the circumference on circle in Tolkien's style. 
Use Sauron's eye as the circle.