Answer: 16 feet 5 inches
Explanation:
From the question, we are informed that the addition to the deck at the back of Kristan house was 7 feet 11 inches on one side and 8 1/2 feet on the other.
To get the total length of saftey rail that they should buy, we would add the value given together. This will be:
= 7 feet 11 inches + 8 feet 6 inches
= 15 feet 17 inches
= 16 feet 5 inches
Nite that 12 inches = 1 foot.
Therefore, the answer is 16 feet 5 inches.