## Thinking Mathematically (6th Edition)

$\dfrac{\sqrt6}{3}$
Rationalize the denominator by multiplying $3$ to both the numerator and the denominator within the radical sign to obtain: $=\sqrt{\dfrac{2}{3} \cdot \dfrac{3}{3}} \\=\sqrt{\dfrac{6}{9}} \\=\sqrt{\dfrac{6}{3^2}} \\=\dfrac{\sqrt6}{3}$