This number, called π (or pi), is approximately 3.14. You have shown that the circumference of a circle is π × diameter.

Defined as the ratio of the circumference of a circle to its diameter, pi, or in symbol form, π, seems a simple enough concept. But it turns out to be an "irrational number," meaning its exact ...

You have shown that the circumference of a circle is π × diameter. ... TIP: Try it with any circular object. Whatever the size, the circumference is always just over 3 × diameter.