What is Pi?

Below are four circular objects. Find the ratio of the circumference to the diameter of each object. (You can find the ratio by dividing the circumference of each circle by its diameter). What do you notice? Now adjust the size of Circle U by dragging point V. Divide the circumference of Circle U by its diameter. You should already know that π ≈ 3.14. How does this compare to the circumference of a circle divided by its diameter?