Question

A child weighs \(70 \mathrm{lb}\) during a pediatric clinic visit. How many kilograms does the child weigh? (Round to the nearest tenth.)

Short answer

The child weighs 31.8 kilograms.

Step-by-step solution

Identify the Conversion Factor

To convert pounds to kilograms, we need to know the conversion factor. The conversion factor from pounds to kilograms is approximately 1 pound = 0.453592 kilograms.

Set Up the Conversion Equation

Using the conversion factor, set up the equation to convert pounds to kilograms. The formula is: weight in kilograms = weight in pounds \(\times\) 0.453592.

Calculate the Weight in Kilograms

Weight in pounds = 70. Now we substitute the value into the equation: \[ 70 \times 0.453592 = 31.75144 \]

Round to the Nearest Tenth

The result from the previous step is 31.75144. We need to round this to the nearest tenth. The digit in the tenths place is 7, and the next digit is 5, which means we round up. Thus, 31.75144 rounds to 31.8.

Key concepts

Pounds to Kilograms Conversion

When converting a child's weight from pounds to kilograms, it's important to understand the basic conversion process. Pounds and kilograms are both units of mass, but they belong to different measurement systems. Pounds are part of the imperial system, commonly used in the United States, while kilograms are part of the metric system, used globally in scientific and most everyday contexts.
Converting weight from pounds to kilograms helps in making health assessments consistent worldwide, especially in pediatrics.
In the given problem, a child's weight of 70 pounds needs to be converted to kilograms. This requires setting up an equation using a specific conversion factor to accurately switch from one unit to the other. Utilizing these conversions ensures standardized communication and calculation in healthcare settings.

Conversion Factor

The key to converting weights is understanding and using the "conversion factor." A conversion factor is a numerical value used to multiply or divide a quantity to change it from one unit to another.
In the case of converting pounds to kilograms, the conversion factor is approximately \( 1 ext{ pound} = 0.453592 ext{ kilograms} \).
This conversion factor allows for precise calculations to ensure accuracy.

• To convert, simply multiply the number of pounds by 0.453592.
• Using the given child weight: \( 70 imes 0.453592 \)
• The result is the weight in kilograms.

By applying this conversion consistently, one can reliably compare weights between the two measurement systems without confusion.

Rounding Numbers

After performing the initial calculation, you might deal with a long decimal number. For ease of use, especially in practical applications like medical dosing or health assessments, it's often necessary to round these numbers.
Rounding a number involves adjusting it to a specified degree of precision. In this exercise, we're asked to round to the nearest tenth.

• Look at the number just after the digit you want to round. If it's 5 or more, round the target digit up.
• For a result of 31.75144, you focus on the second decimal place (5).
• Since 5 is equal to or greater than 5, the first decimal (7) is rounded up to 8.

Thus, 31.75144 becomes 31.8 when rounded to the nearest tenth. Rounding is a vital skill for ensuring clarity and maintaining accuracy in reported measurements.

Pediatric Mathematics

Pediatric mathematics involves applying mathematical principles to child-specific scenarios, often in healthcare. Accurately converting weight is crucial because it directly affects medication dosing, nutritional needs, and growth monitoring.
Children differ from adults in their growth patterns and physiological responses. Therefore, precise calculations are especially significant in pediatrics.
For instance, medication dosages are often determined based on a child's weight. A calculation error could lead to under dosing or overdosing, both of which can have serious implications.

• Accurate weight measurements converted into the correct units ensure that children receive the right care and nutrition.
• Pediatric math needs diligence to prevent errors and promote optimal health outcomes.

By mastering these calculations, healthcare professionals can effectively plan and adapt to each child's unique needs.