1. **Problem statement:** Given that $\log 17 = k$, find an expression for $\log 170$.\n\n2. **Recall the logarithm property:** $\log(ab) = \log a + \log b$. This means the logarithm of a product is the sum of the logarithms.\n\n3. **Express 170 as a product:** $170 = 17 \times 10$.\n\n4. **Apply the property:** $$\log 170 = \log(17 \times 10) = \log 17 + \log 10$$\n\n5. **Substitute known values:** Since $\log 17 = k$ and $\log 10 = 1$ (assuming base 10), we get $$\log 170 = k + 1$$\n\n**Final answer:** $\boxed{\log 170 = k + 1}$