Hei! :)
[tex]\sqrt{\frac{369}{780} } =\frac{\sqrt{369} }{\sqrt{780} } =\frac{\sqrt{9*41} }{\sqrt{4*195}}=\frac{3\sqrt{41} }{2\sqrt{195} }[/tex]
[tex]\frac{3\sqrt{41} }{2\sqrt{39} } :\sqrt{\frac{369}{780} }= \frac{3\sqrt{41} }{2\sqrt{39} } *\frac{2\sqrt{195} }{3\sqrt{41} } =\frac{2\sqrt{195} }{2\sqrt{39} } =\frac{\sqrt{195} }{\sqrt{39} } =\frac{\sqrt{39}*\sqrt{5} }{\sqrt{39} } =\sqrt{5}[/tex]
