The perimeter \( P \) of a square is given by the formula:
\[ P = 4s \]
where \( s \) is the length of one side of the square.
Given that the perimeter of the family room is 16 meters, we can set up the equation:
\[ 4s = 16 \]
To find the length of each side, divide both sides by 4:
\[ s = \frac{16}{4} = 4 \]
So, each side of the family room is 4 meters long.