[tex]\bf \sqrt{\cfrac{3}{16}}\cdot \sqrt{\cfrac{3}{9}}\implies \cfrac{\sqrt{3}}{\sqrt{16}}\cdot \cfrac{\sqrt{3}}{\sqrt{9}}\implies \cfrac{\sqrt{3}}{4}\cdot \cfrac{\sqrt{3}}{3}\implies \cfrac{\sqrt{3}\cdot \sqrt{3}}{4\cdot 3}
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\cfrac{(\sqrt{3})^2}{12}\implies \boxed{\cfrac{3}{12}}\implies \stackrel{simplified}{\cfrac{1}{4}}[/tex]