PA_M7_S3_T2_Converting Metric Length Transcript
When I want to convert between metric units of length I want to keep in
mind that everything is based on powers of 10. So I've set up this table
of values in the top showing the powers of 10 that each of these units
correspond too with my base unit, meters, right and the middle.
Using this concept and powers of 10 I want to change 2326 m to kilometres
I'm going to do it algebraically first. I have 2326 m and I wanted to be
in kilometres so my kilometres are going to be on the top and my meters
are going to be in the bottom. One kilometre is 1000 meters or 10^3
meters but this means I'm going to divide 2326 by 1000 to get my
kilometres. My meters, of course, will cancel.
One of the things that's interesting to note is this is just like working
with decimals. I simply move my decimal on my number the number of places
that I have zeroes in my denominator. I have three zeroes in 1000 so my
decimal place moves to the left three units, and my result is 2.326
kilometres.
Another way to look at it, is that I'm starting at meters right here at
the table and I'm moving three places to the left to get to kilometres.
That's how I move my decimal point.
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Let's change 537 cm to meters. 537 centimeters, I want meters on the top
so my meters go on the top and my centimeters have to go on the bottom so
that they cancel. 1 m is 100 cm, my centimeters cancel and I'm left with
537/100 m. I have two zeroes, so I move my decimal place two units to the
left and I get 5.37 meters.
Let's to do one more, I want to convert 10.2 dekameters to centimeters. I
have 10.2 dam, that's the abbreviation for dekameters, and I want to get
to centimeters. I don't have a direct conversion, so I have to use two
conversions steps. I have 10 m in every single dekameter and I have 100
cm in each meter. My meters cancel, my dekameters cancel, and I get 10.2
* 10 * 100, that's 10.2 * 1000. When I multiply by 1000 I move my decimal
point three units to the right, and I end up with 10,200 centimeters.
I could've done the same thing up here by going from dekameters down to
centimeters, and notice that I move 1, 2, 3 places which means I would
move three units (to the right) and get 10,200 cm.
This is how you convert units of length in the metric system.