Final answer:
The answer to which of the following is equal to 4 kilograms is A. 4,000g. The other options do not correctly represent 4 kilograms when converted into grams, milligrams, or decagrams.
Step-by-step explanation:
The question asks which of the following is equal to 4 kilograms. The correct answer is A. 4,000g. In the metric system, the base unit for mass is the kilogram (kg). One kilogram is equivalent to 1,000 grams (g). Therefore, 4 kilograms is equal to 4,000 grams. Option B is incorrect because 4,000mg represents 4 grams, C is a duplicate of B, and D is incorrect because 40 decagrams (dag) is equal to 400 grams.
Converting between different metric units requires understanding the metric prefixes and their relation to the base unit. For mass, the base unit is the kilogram. Here are some examples of equivalent measures in different units:
- 23 mg (milligrams) is 0.000023kg, or 2.3 × 10-5kg.
- 320 Tg (teragrams) is 320,000,000,000kg, or 3.2 × 1011kg.
- 42 ng (nanograms) is 0.000000000042kg, or 4.2 × 10-11kg.
- 7 g (grams) is 0.007kg or 7 × 10-3kg.
- 9 Pg (petagrams) is 9,000,000,000,000kg, or 9 × 1012kg.
It is often more practical to use the unit that makes for a small and easily managed number when expressing measurements. For example, if you are measuring weight and have a 6.5kg mass, it's more manageable to express it as such instead of 6500g or 0.65 dag, even though all three are correct.