To get the volume of water in gallons we proceed as follows:
volume=length*width*height
the dimension of the pool is:
50m by 25m by 1.5 m
thus the volume will be:
50×25×1.5
=1,875 m^3
but 1 m^3= 1000 liters
therefore:
1,875 m^3=(1875x1000)=1,875,000 liters
converting the above into gallons we get:
1 gallon= 3.786 L
therefore:
1,875,000 L=1,875,000/3.786 gallons
=495,245.6418 gallons