To compare 12 hours to 4 days, we first need to convert the days into hours.
1 day is equal to 24 hours, so: \[ 4 \text{ days} = 4 \times 24 \text{ hours} = 96 \text{ hours} \]
Now we can write the ratio of 12 hours to 96 hours: \[ \text{Ratio} = \frac{12 \text{ hours}}{96 \text{ hours}} \]
Next, we can simplify the fraction: \[ \frac{12}{96} = \frac{1}{8} \]
Thus, the ratio of 12 hours to 4 days in lowest terms is: \[ \frac{1}{8} \]