When converting 115 lbs (pounds) to kg (kilograms), we would multiply by a factor with the following units:
The Correct Answer and Explanation is:
To convert 115 pounds (lbs) to kilograms (kg), you would multiply by a factor with the units kg/lbs, which corresponds to the conversion factor 1 kg / 2.2 lbs. The correct answer is:
Factor: 1 kg / 2.2 lbs
Explanation
Conversion between pounds (lbs) and kilograms (kg) is a common task in healthcare, science, and daily life. Pounds and kilograms are units of mass in different systems: pounds belong to the Imperial system, and kilograms belong to the Metric system.
Step-by-Step Conversion:
- Understand the relationship:
- The conversion factor between pounds and kilograms is approximately 1 kg = 2.2 lbs. This means that 1 kilogram is equal to 2.2 pounds. Therefore: 1 lb=1 kg2.21 \, \text{lb} = \frac{1 \, \text{kg}}{2.2}1lb=2.21kg
- Determine the correct factor:
- When converting from pounds to kilograms, you need a factor that cancels out the pounds and leaves the result in kilograms. This factor is: 1 kg2.2 lbs\frac{\text{1 kg}}{\text{2.2 lbs}}2.2 lbs1 kg
- Apply the factor:
- For 115 lbs, multiply by the factor: 115 lbs×1 kg2.2 lbs=1152.2 kg115 \, \text{lbs} \times \frac{1 \, \text{kg}}{2.2 \, \text{lbs}} = \frac{115}{2.2} \, \text{kg}115lbs×2.2lbs1kg=2.2115kg
- Perform the calculation:
- Dividing 115 by 2.2 gives: 115÷2.2=52.27 kg (approximately)115 \div 2.2 = 52.27 \, \text{kg} \, (\text{approximately})115÷2.2=52.27kg(approximately)
Why This Works:
The unit factor method ensures the original units (lbs) cancel out, leaving the desired unit (kg). Using the reciprocal factor (2.2 lbs / 1 kg) would incorrectly result in pounds squared per kilogram, which is not meaningful in this context.
In healthcare, precise weight conversions are critical for medication dosages, fluid management, and other clinical decisions. Always verify calculations for accuracy, especially when patient safety is involved.