Question 491759
{{{1/sqrt(28)}}} is not a question, so there's no answer to it.
You can simplify it, and "rationalize" the denominator, ie, get the radical out of the denominator.
---------------------
It's important to know and say what you want to do.
---------------------
{{{1/sqrt(28) = sqrt(28)/28}}}
= {{{sqrt(4)*sqrt(7)/28}}}
= {{{2sqrt(7)/28}}}
= {{{sqrt(7)/14}}}