When the pool is half full of water, the height of the water is 3 feet. This means that when the pool is completely full of water, the height of the water is 6 feet, and this corresponds to the length of the side of the cube-shaped pool. Therefore, the volume of the pool is the volume of a cube with side of 6 feet:
[tex]V=L^3 = (6 ft)^3 = 216 ft^3[/tex]
