What is the square root of 72 in simplest form?

Answer 1

Given the phrasing of your question, that could be a matter of debate.

First, the square root of 72 is actually 8.48528137, at least that is accurate to within 1/10,000,000th.

As far as "simplest" goes, that is the answer.

There is a concept of a "simplified radical form" that you may actually mean.

If so, the answer is 6 times the square root of 2. This represents the fact of 36 times 2 equalling 72, and six being the square root of 36. The square root of 2 starts out as 1.414 and is by no definition "simple", so we simply say "six times the square root of two" as opposed to "six times 1.414...forever in a non-repeating way".
6 root 2