[tex]\sqrt{5\frac{1}{4} } \cdot\sqrt{\frac{7}{9} }=\sqrt{\frac{21}{4}\cdot \frac{7}{9} }=\sqrt{\frac{7}{4} \cdot\frac{7}{3} }=\frac{\sqrt{49} }{2\sqrt{3} }=\frac{7}{2\sqrt{3} }\cdot\frac{\sqrt{3} }{\sqrt{3} } =\frac{7\sqrt{3} }{2\cdot3} =\frac{7\sqrt{3} }{6}[/tex]
