Video Transcript
Convert ten million centimeters into kilometers.
Now centimeters and kilometers are both lengths in the metric measuring system. Now in that system, the basic measure of length is the meter, and then we have fractions of meters and we have multiples of meters.
So to give you an idea of what a meter is, the average car height is about one point four one point five meters, so one meter is about two-thirds as tall as the average car.
The word kilo means a thousand, so a kilometer or a “kee-lo-mee-ter” is a thousand meters, and the word centi means a hundredth of, so one centimeter is a hundredth of a meter; a hundred centimeters make up one meter.
So if I start off with ten million centimeters, each group of a hundred centimeters is gonna make up one meter. That means there are a hundred times as many centimeters as there are meters. So I need to divide ten million by a hundred to work out how many meters this is equivalent to.
Now that might look a bit weird because I said you take one meter and divide it by a hundred to get one centimeter, and then I said take the number of centimeters and again divide it by a hundred and that turns it into meters.
Well both of those things are right. A centimeter is one hundredth of a meter, so if I take the number of centimeters, I would need to divide that by a hundred to get the number of meters, and likewise for meters in kilometers.
A kilometer is made up of a thousand meters; it’s a thousand times as big as a meter. So if I have a measurement, there are gonna be a thousand times as many meters in that measurement as there are kilometers.
And that means if I want to convert the number of meters into the number of kilometers, I’m gonna have to divide that number by a thousand. And that’s gonna give me one hundred kilometers.
Let’s just work backwards and check that. If I’ve got one hundred kilometers, every one of those kilometers is a thousand meters, so in terms of meters it’s gonna be a thousand times a hundred, a hundred thousand meters.
And each one of those meters is made up of a hundred centimeters, so there are gonna be a hundred times more centimeters than there are meters. So that’s gonna be a hundred times a hundred thousand centimeters, and that is ten million centimeters, which was what we were asked to do in the question. So looks like we’re right.
