Final answer:
To convert pounds to kilograms, multiply the weight in pounds by 0.4536. Use significant figures based on the inexact number's precision. When adding weights, sum them directly if they are already in kilograms.
Step-by-step explanation:
To convert a resident's weight in pounds to kilograms, you will use the conversion factor where 1 pound is equivalent to 0.4536 kilograms. For instance, if you have a weight of 100 pounds, you would multiply 100 by 0.4536 to get the weight in kilograms. In this example, the weight in kilograms would be 45.36 kg. It's important to remember that when converting to a smaller unit you should maintain the number as manageable and easy to comprehend as possible, using the unit that best fits the context of the problem.
When working with significant figures, if you have an inexact number such as 2.205, the significant figures of that inexact number dictate the significant figures in your answer. Therefore, if you are converting pounds to kilograms, make sure to respect the significant figures in your final answer.
If you need to add weights in kilograms, simply sum them as you would normally add numbers. For instance, if you have weights of 2.5 kg and 3.5 kg, their total sum is 6 kg.