Question 41·Medium·Ratios, Rates, Proportional Relationships, and Units
A cylindrical aquarium is completely filled with water and holds 47 gallons. Approximately how many cubic inches of water does the aquarium contain?
Use the following conversion factors:
(Express the answer as an integer)
For unit-conversion questions, use dimensional analysis: write the starting quantity and multiply by conversion factors as fractions so that units cancel step by step. Track units carefully, especially with squared or cubed units—remember that if a length conversion uses a factor of , then an area conversion uses and a volume conversion uses . Combine all conversions into one clean expression, evaluate with your calculator, and then round only at the end to save time and reduce error.
Hints
Start with gallons to liters
You are given 47 gallons and a gallon-to-liter conversion. What do you multiply 47 by to find the number of liters?
From liters to cubic centimeters
Once you know the volume in liters, use the fact that liter cubic centimeters. How does that change the number?
Be careful with cubic units
You know inch centimeters. For volumes, how many cubic centimeters are in cubic inch? Should you multiply or divide by to go from cubic centimeters to cubic inches?
Put all conversions together
Write one expression that starts with 47 and applies all three conversions in order. Then evaluate that expression and round reasonably.
Desmos Guide
Compute all conversions in one expression
In Desmos, type the single expression:
47 * 3.785 * 1000 / (2.54^3)
The output of this expression is the approximate number of cubic inches of water in the aquarium. Use that value, rounded to the nearest whole number, as your answer.
Step-by-step Explanation
Convert gallons to liters
Use the first conversion factor: gallon liters.
So for gallons:
The aquarium contains liters of water.
Convert liters to cubic centimeters
Use the second conversion factor: liter cubic centimeters.
Multiply the liters by :
So the volume is cubic centimeters.
Set up the conversion from cubic centimeters to cubic inches
Use the third conversion: inch centimeters.
For volume, this means:
- inch cm
- cubic inch cubic centimeters
So:
To convert from cubic centimeters to cubic inches, divide by :
Calculate and approximate the final volume in cubic inches
First compute :
Now divide the cubic centimeters by this value:
Rounding to the nearest whole number gives about cubic inches.
So, the aquarium contains approximately 10,856 cubic inches of water.