3:9 17

$${\frac{3}{17}} : 9 = {\frac{3}{17}} \cdot {\frac{1}{9}} = {\frac{3}{17 \cdot 9}} = {\frac{3}{17 \cdot 3 \cdot 3}} = {\frac{1}{17 \cdot 3}} = {\frac{1}{51}}$$

Ответ: $$\frac{1}{51}$$