# Keyword Analysis & Research: rational numbers are closed under

## Keyword Research: People who searched rational numbers are closed under also searched

Yes the square root of 5 is an irrational number. Here is a proof (by contradiction) I will assume that $\sqrt5$ is a rational number.\\. This means that it can be expressed as $\dfrac{a}{b}$ where $a\; and \;b$ \\are relatively prime integers (that means they have no common factors other than 1)\\.