The answer is [tex] \frac{ \sqrt{6} }{3} [/tex] .
We start from the square root of 2/3: [tex] \sqrt{ \frac{2}{3}} [/tex]
Then we must find how much times we must multiply both numerator and denominator to get the square root of denominator as an integer:
[tex] \sqrt{ \frac{2}{3} }= \sqrt{ \frac{2*3}{3*3} } = \sqrt{ \frac{6}{9} } = \frac{ \sqrt{6} }{ \sqrt{9} }= \frac{ \sqrt{6} }{3} [/tex]
