We extend modular arithmetic to the real numbers.
Two real numbers $x, y \in \R $ are congruent modulo $\alpha \in \R $ if their difference is a multiple of $\alpha $
For $x, y \in \R $, if $x$ and $y$ are
congruent modulo $\alpha \in \R $ we write
\[
x \equiv y (\mod \alpha )
\]