Question 20588
Hello There:

We need to know two things to answer this question.

1) How to calculate the volume of the tank in cubic inches (we use inches because that's the unit of measurement we are given).

2) Finding out how many cubic inches there are in one gallon of water.

Let's do #1 first.  The volume of a rectangular container is Length times Width times Height.

V = 18*10*9

V = 1620

The fish tank holds 1,620 cubic inches of water.

Now we do #2.  I did not know how to convert gallons into cubic inches, so I went to the following site:

http://www.onlineconversion.com/volume.htm

Here, I found out that 231 cubic inches equals 1 U.S. liquid gallon.

Now it's just a matter of finding out how many 231 cubic inch amounts there are in the fish tank.

1620/231 = 7.01

The fish tank holds 7 gallons of water.

~ Mark