[tex]\displaystyle\bf\\\sqrt{3\frac{19}{27} } =\sqrt{\frac{100}{27} } =\sqrt{\frac{10^{2} }{3^{2}\cdot 3 } } =\frac{10}{3} \cdot\sqrt{\frac{1}{3} } =3\frac{1}{3} \cdot\frac{1}{\sqrt{3} }[/tex]