Answer:
3 feet
Step-by-step explanation:
A cube has 6 square congruent faces, thus
area of 1 face = [tex]\frac{54}{6}[/tex] = 9 ft²
The area of a square = s² ← s is the length of a side, hence
s² = 9 ( take the square root of both sides )
s = [tex]\sqrt{9}[/tex] = 3