The square root of 1 is 1, but the square root of 18 needs to be explored. 18 is 9*2, and 9 is a perfect square. So let's rewrite our original problem using that fact:
![\sqrt{ (1)/(18) } = \sqrt{ (1)/(9*2) }](https://img.qammunity.org/2019/formulas/mathematics/high-school/vpcmhi41381da8ovovmm8r5zpjnoe04pal.png)
. We can pull out the square root of 1 as 1 and the square root of 9 as 3, leaving the 2 behind:
![\sqrt{ (1)/(9*2) } = (1)/(3) \sqrt{ (1)/(2) }](https://img.qammunity.org/2019/formulas/mathematics/high-school/1odprr3gpc7nw54txaen633uthiiajjyvx.png)
. And there you go!