Answer: 6 feet by 3 feet
Explanation:
The box cannot be congruent (meaning the same size) but has to be similar. Similar means same shape but either larger or smaller by a scaled amount. In this case, the garden has to be smaller. We just need to find a scale factor that works for both 12 and 6. The only possible answer that works is 6 feet by 3 feet. This would mean the original garden would be scaled down by half.
12/2= 6
6/2= 3