Quotient Group of Reals by Integers is Circle Group

Theorem
Let $\left({\Z, +}\right)$ be the additive group of integers.

Let $\left({\R, +}\right)$ be the additive group of real numbers.

Let $K$ be the circle group.

Then the quotient group of $\left({\R, +}\right)$ by $\left({\Z, +}\right)$ is isomorphic to $K$.