Final answer:
The metric mass approximately equal to 2.2 pounds is 1 kilogram, as one kilogram is defined to be about 2.2 pounds.
Step-by-step explanation:
The metric mass that is approximately equal to 2.2 pounds is 1 kilogram (kg). This is because one kilogram is about 2.2 pounds by definition in the SI (International System of Units). Therefore, option a, which states 1 kilogram, is the correct answer. The other options given:
b. 500 grams is equal to 0.5 kg, which is less than 2.2 pounds.
c. 500 milligrams (mg) is equal to 0.0005 kg, which is much less than 2.2 pounds.
d. 1 milligram is equal to 0.000001 kg, which is significantly less than 2.2 pounds.
One kilogram is approximately equal to 2.20462 pounds. Therefore, a metric mass that is approximately equal to 2.2 pounds is 1 kilogram. This conversion is commonly used when transitioning between the metric system, which is based on units like kilograms, and the imperial system, where pounds are the standard unit of mass.
The conversion factor between kilograms and pounds is often rounded to 2.2 for simplicity. So, when you encounter a mass measurement in pounds and need a quick estimate in the metric system, you can use the 2.2 pounds to 1 kilogram conversion.
This equivalence is especially useful in everyday contexts, such as when comparing weights on food labels or discussing personal body weight in different measurement systems.