To convert from one unit of measurement to another, a conversion factor must be equal to what?

• A. 0
• B. 1
• C. 10
• D. 100

Answer: (B)

A conversion factor must be equal to 1 because it is a ratio that expresses the relationship between two different units of measurement. When you multiply a quantity by a conversion factor, you are essentially rewriting that quantity in a different unit without changing its actual value. For instance, if you are converting inches to centimeters, the conversion factor would be 2.54 centimeters per inch, which is equal to 1 inch. This means that using this factor maintains the equivalence of the measurements, thereby ensuring accuracy in calculations. If the conversion factor were not equal to 1, it would suggest that there is a value change, which is not the case when merely converting between units.