1. **State the problem:** We have 19 swans, 67 ducks, and 33 geese on a lake. We need to write the ratio of swans to ducks to geese in the form $1 : m : n$ where $m$ and $n$ are decimals rounded to 2 significant figures. 2. **Write the ratio:** The original ratio is $19 : 67 : 33$. 3. **Convert to the form $1 : m : n$:** Divide each part of the ratio by the number of swans, 19. $$1 : \frac{67}{19} : \frac{33}{19}$$ 4. **Calculate the decimal values:** $$m = \frac{67}{19} \approx 3.5263 \rightarrow 3.5 \text{ (2 significant figures)}$$ $$n = \frac{33}{19} \approx 1.7368 \rightarrow 1.7 \text{ (2 significant figures)}$$ 5. **Final ratio:** $$1 : 3.5 : 1.7$$ This means for every 1 swan, there are approximately 3.5 ducks and 1.7 geese.