And a conversion factor is just a number
that relates amount of one thing to the amount of another thing, and it’s
always equal to our favorite number 1. And we’ve already seen how
to use a conversion factor to go from number of
cartons to number of eggs. And the conversion factor we used was 12
eggs divided by 1 carton, but cartons and eggs aren’t the only thing that we
can convert using a conversion factor. We can convert between units of
distance, or volume, or even money. If we have the correct
conversion factor, for example, let’s look at yards to feet. There are three feet in every
yard which means 3 feet=1 yard, in the same way that 12 eggs
was equal to one carton. But that’s not quite
our conversion factor. The conversion factor is 3
feet divided by 1 yard and this is equal to 1 since these
quantities are identical. So let’s practice using one
of these conversion factors. Let’s say that you
need 4 yards of ribbon. I don’t know, maybe you’re having
a birthday party or something. But the store you’re in
sells ribbon by the foot. How many feet of ribbon should us for