You can only measure anything to within a finite precision anyway. You won't measure exactly Pi inches, but you also won't ever measure exactly 1 inch. You are

You can only measure anything to within a finite precision anyway. You won't measure exactly Pi inches, but you also won't ever measure exactly 1 inch. You are limited by your equipment's precision. Electromagnetism is full of both e (exponential decay, etc) and Pi (charges rotate, polarization rotates, etc).