\( \sqrt{\frac{1}{9}x^2y^6} \) при \(x=7, y=3\);

\( \sqrt{\frac{1}{9}x^2y^6} = \sqrt{\frac{1}{9}(7^2)(3^6)} = \sqrt{\frac{1}{9}49 \cdot 729} = \sqrt{4009} \approx 63.3.\)