(6) / (4.5) = 4 / 3 = 1.333...
The level increased by 33-1/3 % .
The old level was 75% of the new level.
The amount of water in the pool also had to
increase 33-1/3 % . If you didn't have that
much water to put in the pool, you couldn't
change the surface level from 4.5ft to 6ft .
