9 is the length.
Volume=cross sectional area (the base of the tank) x height
8 is the height
648 is the volume
648=y x 8
Y is the cross-sectional area
So you have to do 648 divided by 8
Which is 81
So 81 is the area
But since its the area of a square
All the sides are the same length
So all you have to do is square root 81 which equals 9.
The answer is 9
