[tex]R = \frac{18}{ \sqrt{2} } = \frac{18}{ \sqrt{2} } \times \frac{ \sqrt{2} }{ \sqrt{2} } = \frac{18 \sqrt{2} }{2} = 9 \sqrt{2} [/tex]
[tex]R = \frac{3 \sqrt{2} }{ \sqrt{2} } \: [/tex]
simplificam cu radical din 2
[tex]R= 3[/tex]
