00:02
Hi there.
00:03
For each of these pairs of units, we are asked to write an equality and then two conversion factors.
00:11
So let's talk about what the conversion factor is as we do the first one here.
00:14
So first we want an equality between centimeters and inches.
00:19
There are 2 .54 centimeters in each inch.
00:31
All right, so that is the equality.
00:33
We can write this since 2 .54 centimeters equals one inch.
00:38
We can write this as a conversion factor.
00:41
In other words, a fraction, where since the numerator is equal to the denominator, that fraction is going to be equal to one.
00:49
So the two conversion factors we can write is we can write one of them with centimeters in the numerator and inch in the denominator, or we could reverse it.
01:06
We could have one inch in the numerator and 2 .54 centimeters in the denominator.
01:17
And it's just the problem that we are doing that would determine which of these conversion factors we wanted to use.
01:23
Are we trying to convert from inches to centimeters or are we trying to convert from centimeters to inch? so that would determine which of these two conversion factors we would use in the actual problem.
01:35
But the equality is the same.
01:37
It just changes which unit we put in the numerator and which one we put in the denominator.
01:42
All right, so let's go on.
01:44
Letter b, kilometers and miles.
01:48
One kilometer is equal to 0 .6214 miles.
02:01
Runners have a pretty good concept of this because they typically run 5k races or 10k races.
02:09
So they have a little bit of a feel for how a kilometer is greater than a mile.
02:15
All right, so that's the equality.
02:16
Let's write this as our two conversions...