Answer:
length, width, perimeter
Explanation:
First of all, you should notice that no problem is posed. A description is given, but no question is asked about it.
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If we assume that the length and width of the patio are desired, then those are the selections for the first two boxes.
The only other characteristic of the situation that is provided is the perimeter. So the formula for perimeter is the only one that can be usefully used.