1. **State the problem:** We have a map scale of 1 : 200000, meaning 1 cm on the map represents 200000 cm in real life. 2. **Given:** Length on map = 4 cm. 3. **Formula:** Real length = Map length \times Scale factor. 4. **Calculate real length in cm:** $$\text{Real length} = 4 \text{ cm} \times 200000 = 800000 \text{ cm}$$ 5. **Convert cm to km:** Since 100 cm = 1 m and 1000 m = 1 km, then 100000 cm = 1 km. 6. **Convert:** $$\frac{800000 \text{ cm}}{100000} = 8 \text{ km}$$ 7. **Answer:** The length of the road in real life is **8 kilometres**.