# How do we rationalize a denominator?

##### 1 Answer

Apr 3, 2016

Multiply the whole fraction by the denominator over itself.

#### Explanation:

If you have a fraction where the denominator (bottom number) is irrational, such as a square root, then multiply the whole fraction by the denominator divided by itself.

Take the example

which has a rational denominator.

Multiply the entire fraction by the denom. divided by itself, like so

More examples are

In this last example I turned