[tex]\it c)\ \sqrt{\dfrac{^{2)}3}{200}}=\sqrt{\dfrac{6}{400}}=\dfrac{\sqrt6}{\sqrt{400}}=\dfrac{\sqrt6}{20}\\ \\ \\ a)\ \sqrt2\cdot\sqrt6=\sqrt{12}=\sqrt{4\cdot3}=2\sqrt3\\ \\ \\ d)\ \sqrt{15}\cdot\sqrt6=\sqrt{15\cdot6}=\sqrt{90}=\sqrt{9\cdot10}=3\sqrt{10}[/tex]
