Answer:- If he has 86 boards then they are altogether 3,655 inches long .
Explanation:-
Given: Robert is building a deck in his backyard.
Measure of each piece of wood=42.5 inches
If he has 86 boards to make deck , then
Length of deck = 86 × 42.5 inches
⇒Length of deck=3,655 inches.
Therefore, If he has 86 boards then they are altogether 3,655 inches long .
