Convert 51.8 decimeters

to kilometers. So let’s just think about what

decimeters means in terms of meters, and then we can think

about what kilometers mean in terms of meters, and

then convert them. So we’re going to start

with 51.8 decimeters. Now, as a starting point, just

to keep things simple, we’re going to convert them into

meters, because this prefix tells us a lot about how

many meters this is. So if we want to convert it

into meters, our units are going to have to be meters

per decimeter. And we need this because this

decimeter and that decimeter are going to cancel out, and

we’re going to be just left with meters. Now 1 meter is how

many decimeters? Well, the prefix deci

means 1/10. So 1 decimeter is

1/10 of a meter. Or another way of thinking

about it is there are 10 decimeters for every meter. This is a smaller unit. 10 of these make up 1 of these,

or 1/10 of a meter per decimeter, which is exactly

what that is telling you. 1/10 of a meter. Now if you multiply these two

things, what do we get? Well, the decimeters cancel out,

and we divide 51.8 by 10. Multiplying by 1/10 is the same

thing as dividing by 10. So this is going to be equal

to 51.8 divided by 10. The decimal’s just going

to move to the left. It’s going to be 5.18. So this is going to

be 5.18 meters. And you should always

do a reality check. Did it make sense? Does it make sense that

51 decimeters are equal to 5 meters? Well, sure. It should go down. We’re going from a smaller unit

to a larger unit, so we should have fewer of that larger

unit to make the same distance in this case. A meter is a unit of length. Now, we’re at 5.18 meters, and

we want to now convert it to kilometers. So we’re going to want meters

in the denominator and kilometers in the numerator. Why? Because this meter and that

meter will cancel out. Now, how many meters make

up a kilometer? The kilo tells us 1,000. That is 1,000 meters. So 1,000 meters are equal

to 1 kilometer. So if we were to multiply this,

the meters cancel out and we’ll just be left

with kilometers. And multiplying something by

1/1,000 is the exact same thing as dividing by 1,000,

and that makes sense. We should get a smaller number

here because we’re going from a smaller unit to

a larger unit. So we’re going to need

a much smaller amount of the larger unit. So this is going to be equal

to 5.18/1,000 kilometers. Now, the easy way to do this,

if we take 5.18/10 is equal to– we just move the decimal

one to the left. It’s going to be

equal to 0.518. If we take 5.18 and divide it

by 100, we’re going to take the decimal two to the left. So one, two, we’re going to

have to add a zero here. So it’s going to be 0.0518. And if we take 5.18 and we

divide by 1,000, we’re going to move the decimal

three to the left. So we’ll just do it. So if we start with 5.18– the

decimal started here– we’re going to go one, two,

so that’s one zero, and then three. And that’s where the decimal

is going to sit there. So this is Or another way, this

is a little over 5/1,000. This right here is 5/1,000. It’s a little bit

more than that. So our final answer: 51.8

decimeters is equal to 0.00518 kilometers. And always do a reality check. Does that make sense? Well, sure. We’re going from a really small

unit here, a bunch of a small unit, to a very small

amount of a large unit. It makes sense. It makes sense that this number

goes down while the actual unit becomes larger.

King Henry died monday drinking chocklate milk

Thanks sooo much!!!! For this video!

What about significant digit?

@XLyeeb that only applies if it were chemistry.

@Tyncidog we do king henry unexpectedly died drinking chocolate milke!!

@healbyGod im glade i found this while im still in college

Just incase anyone is wondering the secret to college. Just get a job with the school, they drop the price to almost nothing. YW

You're a geographical characteristic that you found this…? How are you even in college?!?

lol what??!? How am i in college? Well to start i make can speak

Thank you so much for the vid. You just helped me so much. Keep up the work!

khan acedemy!!!!!!

i didn't understand……..hm

This explanation makes it harder then it has to be IMO. Just move the decimal point. There are a few other videos here on Youtube which do it right.

boring and stupid

excellent

All of a sudden this all made sense! Thank you!

Thank you very much

now It suddenly make sense

You are a symbol of pure education.

my teacher taught us a way with adding 0's but I like this way a lot better !

Awesome!!!! Love Khan Academy! Keep up the good work.

where did the 100 come from?

Thanks!

thanks

math and science yo (^-^)*the more you know

but probily not on youtube srry

I was 223 like

and subscribe

This makes it way more complicated…

Thank you Khan! I´m really starting to understand after this video!

I don't understand…

like si estas por la maestra de ingles

+Khan Academy this makes no sense

khan ac5d3m9 4 lif3

That is the wrong answer if you do not believe me go search a unit converter.

Thanks for the help Khan!!!

Thanks for no help 👎🏽😐😑😥😥😭

i love it

All over the place

Thanks alot

Wow thanks for the vid keep up the good work and have fun