1. **Problem Statement:** We need to find the time when the temperature first reached 67°F based on the given temperature vs. time graph. 2. **Understanding the Graph:** The temperature starts at 60°F at 6 am and rises to about 67°F near 9 am. It continues to rise to 70°F by 12 noon. 3. **Approach:** Since the temperature rises steadily from 60°F at 6 am to 67°F near 9 am, we can estimate the time when it first reached 67°F by linear interpolation between these two points. 4. **Linear Interpolation Formula:** $$ T = T_1 + \frac{(T_2 - T_1)}{(t_2 - t_1)} \times (t - t_1) $$ where $T$ is the temperature at time $t$, $T_1$ and $T_2$ are temperatures at times $t_1$ and $t_2$ respectively. 5. **Given Values:** - $T_1 = 60$°F at $t_1 = 6$ am - $T_2 = 67$°F at $t_2 = ?$ (we want to find the exact time when temperature is 67°F) 6. **Since the graph shows 67°F near 9 am, we check if it matches linear interpolation:** - The temperature rises from 60°F at 6 am to 67°F at 9 am, so $t_2 = 9$ am. 7. **Conclusion:** The temperature first reached 67°F at approximately 9 am. **Final Answer:** The temperature first reached 67°F at about **9 am**.