1. **Problem statement:** We need to find how long the temperature held steady based on the graph showing temperature over time. 2. **Understanding the graph:** The temperature rises from 50°F at 6 am to 65°F at 12 noon. 3. Then, the temperature remains steady at 65°F from 12 noon to 6 pm. 4. Finally, the temperature falls from 65°F at 6 pm to 55°F at 12 midnight. 5. **Finding the duration of steady temperature:** The temperature is steady between 12 noon and 6 pm. 6. Calculate the time difference: $$6\text{ pm} - 12\text{ noon} = 6\text{ hours}$$ 7. **Answer:** The temperature held steady for 6 hours.