To find the missing value in the conversion chart between kilometers and miles, we can use the conversion factor that 1 kilometer is approximately equal to 0.621371 miles.
Given that 20 kilometers corresponds to the missing value in miles, we can calculate it as follows:
\[ 20 \text{ km} \times 0.621371 \text{ miles/km} \approx 12.4274 \text{ miles} \]
Looking at the options provided: 6, 5.4, 11.1, and 12, we see that 12 is the closest to the calculated value of approximately 12.43, therefore:
The missing value in the table is 12.