Answer:
C: 8 feet
Explanation:
You have to find the parameter.
To do that you add all the side lengths together.
15+15=30 now you have to subtract 30 from 46 to find how much room is left.
46-30=16 now divide your answer by 2 to get the 2 remaining sides of the deck.
16/2=8 so the answer is 8!