Answer:
21x21 cm
Explanation:
Volume =whl
Given: V=486, and h=6, and w=l
So we can it into this equation: 486=6(l^2)
to solve we isolate the variable by dividing each side by factors that don't contain the variable.
which therefore l = 9
Then we add 6(height) +9(l)+6(width)
6+9+6=21 therefore the sides of cardboard are 21 cm × 21 cm