Write two ratios comparing the number of pounds to the equivalent number of kilograms. Recall that 1 pound is about 0.45 kilogram.
about 40.5
Practice makes perfect
We want to use a proportion to complete the given statement. Let's take a look at it.
To write the proportion we will need two ratios. First one can compare the number of pounds we want to convert to kilograms to the equivalent number of kilograms, x. The second one will be the relationship between pounds and kilograms. Recall that 1 pound is about 0.45 kilogram. We can use these information to construct the ratios.
90pounds is about xkilograms:& 90/x [1.5ex]
1pound is about 0.45kilogram:& 1/0.45
Now, we can write our proportion. To do so, we simply need to put an equality sign between the two ratios. Note that the ratios are equivalent, because both of them describe the relationship between pounds and kilograms.
90/x = 1/0.45
Finally, we will solve the proportion. There are a few ways to do so, but for simplicity we can use the Cross Products Property. It tells us that cross products of a proportion are equal. Let's calculate cross products and solve for x!
The result means that 90 pounds is about 40.5 kilograms. Note that it is an approximation, because we used a rounded number to express how many kilograms is 1 pound. Finally, we can complete the given statement.
