# Pi (π)

### Explained Visually

By Victor Powell

Before we define π, let's define a circle. A circle is a set of points that all lie an equal distance away from a single center point. The distance from the center point is called the
and the distance along the outer edge of the circle is called the
. The
is the thickness of the circle at its widest and is 2 times the
.

π is the ratio of the
to the
and this ratio holds true of all sizes of circles. Because of this, π is a constant and equal to approximately 3.14. But don't get hung up on the idea that the decimal number representation of 3.14 is somehow special or mystical. It could have instead been defined as the
over the
and in fact, this might have made more sense. (see: Tau Day.)

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