$${\mathtt{2}}{\mathtt{\,\times\,}}{\sqrt{{\mathtt{3}}}}$$
Prime factorization of 12 leaves $${\sqrt{{\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{3}}}}$$ take out the 2s and there is your answer.
$${\mathtt{2}}{\mathtt{\,\times\,}}{\sqrt{{\mathtt{3}}}}$$
Prime factorization of 12 leaves $${\sqrt{{\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{3}}}}$$ take out the 2s and there is your answer.