PI is aid to be the ratio of the circumference of a circle to its radius. PI is an irrational number, meaning it cannot be represented as a fraction of two whole numbers. But it is impossible to travel or measure an irrational distance, which leads to questioning whether a circle is a reality or not.
But there is another way of defining a circle provided by the pythagorean theorem, r** = x** + y**. This produces a locus of points said to be all all equidistant from the center. However, there is a caveat, ie, r is an irrational distance. ` So how do we know that all points are equidistant from the center?