Rationalization (mathematics)

The rationalization of denominators is to get rid of radicals that are in the denominator (the bottom part of a fraction). It works by dividing the bottom radical by itself, then multiplying that by the first expression.

${\frac {a}{\sqrt {b}}}={\frac {a}{\sqrt {b}}}\times {\frac {\sqrt {b}}{\sqrt {b}}}={\frac {a{\sqrt {b}}}{{\sqrt {b}}^{2}}}={\frac {a{\sqrt {b}}}{b}}$