Lesson 4: Conversions Between SI and Imperial - Mass Conversions

   Constructing Knowledge

Both SI and imperial mass units are also commonly used. For example, in a grocery stores, it is common for meat prices to be given in both pounds and kilograms. Use proportional reasoning to convert between mass units in the SI and imperial systems.

   Multimedia

A video demonstrating mass conversions between the SI and Imperial system is provided.



EXAMPLE 1

The worldwide average weight of an adult is approximately 137 lbs. What is the worldwide average weight of an adult, in kilograms?

Solution


\(\begin{align} \frac{x}{137\,\text{lbs}}&=\frac{0.454\,\text{kg}}{1\,\text{lb}} \\ \\ \frac{x}{\cancel{137\,\text{lbs}}}\times {\color{red}{\cancel{137\,\text{lbs}}}}&=\frac{0.454\,\text{kg}}{1\cancel{\text{lb}}}\times \color{red}{137\cancel{\text{lbs}}} \\ \\ x&=62.198\,\text{kg} \\ \end{align}\)

The worldwide average weight of an adult is approximately 62.2 kilograms.

EXAMPLE 2

The largest nugget of gold found in Canada is 45.15 ounces. What is the value of the nugget if gold is valued at $52.00 per gram?

Solution


Step 1: Convert 45.15 ounces to grams.

\(\begin{align} \frac{x}{45.15\,\text{oz}}&=\frac{28.35\,\text{g}}{1\,\text{oz}} \\ \\ \frac{x}{\cancel{45.15\,\text{oz}}}\times {\color{red}{\cancel{45.15\,\text{oz}}}}&=\frac{28.35\,\text{g}}{1\cancel{\text{oz}}}\times \color{red}{45.15\cancel{\text{oz}}} \\ \\ x&=1280.0025\,\text{g} \\ \end{align}\)

Step 2: Determine the value of the gold nugget.

value = number of grams × value/gram
= 1280 grams × $52.00/gram
= $66 560.13


The value of the gold nugget would be $66 560.13


Now, it is your turn! Complete the questions in your Chapter 5, Lesson 4 Practice Makes Perfect that refer to Mass Conversions.



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