Ratios Introduction - what are ratios? - By tecmath
Transcript
| 00:02 | Good day . Welcome to the Tech Math channel . | |
| 00:03 | What we're going to be having to look at in | |
| 00:05 | this video is ratios . This is just a basic | |
| 00:09 | introduction into ratios . And in some later videos , | |
| 00:12 | we will be looking at how to play around with | |
| 00:15 | these and work out some more complex things with them | |
| 00:17 | . So first off , what is a ratio ratio | |
| 00:20 | is away of comparing uh , two or more sets | |
| 00:24 | of quantities . I'll give you an example . That | |
| 00:26 | that sounds a little bit funny . So say I | |
| 00:28 | was looking at the amount of cordial in a drink | |
| 00:31 | . Okay . So I bought myself some cardio mary | |
| 00:33 | into a drink and I could say something like on | |
| 00:36 | earning Every three parts cordial , 1 , 2 , | |
| 00:39 | 3 , three parts cordial . I have seven parts | |
| 00:45 | water . one , Okay , So this would be | |
| 00:53 | said to have a ratio of three parts 273 is | |
| 00:57 | 27 Okay . And this is how we write these | |
| 00:59 | . All right . So we're comparing one quantity to | |
| 01:04 | another quantity . So they're pretty simple . And you | |
| 01:06 | can do this with all sorts of quantities . Okay | |
| 01:08 | ? Uh whether it be things to do with weight | |
| 01:11 | or just even share amounts of things and we'll go | |
| 01:13 | through a few examples with this . So just a | |
| 01:15 | couple of things with ratios . The first one is | |
| 01:19 | this I guess the first thing I want to tell | |
| 01:21 | you is that units are important with ratios I'll give | |
| 01:24 | you an example . Say I wanted to compare three | |
| 01:29 | cm to a measurement of 20 centimeters . You'll notice | |
| 01:35 | That these are both in cm . It's fairly simple | |
| 01:38 | . We could say that these had a ratio . | |
| 01:39 | You guessed it is three Yes . 20 . Okay | |
| 01:45 | . We don't actually write the units . We just | |
| 01:47 | write it has a ratio of three is 20 but | |
| 01:50 | I'll make this a little bit hard in there . | |
| 01:52 | Say for example , I changes this too Or change | |
| 01:58 | it to two m . Now , how would you | |
| 02:00 | write a ratio of these two amounts ? Because you | |
| 02:02 | noticed that we have different units . So we're going | |
| 02:05 | to change one of these units . I'm not going | |
| 02:06 | to change the cm , you're going to leave that | |
| 02:08 | the same 3cm , but I'm going to change this | |
| 02:11 | so that the two m is also in centimeters , | |
| 02:13 | there's 100 centimeters in a meter . So this is | |
| 02:16 | 200 centimeters . Now we can easily write a ratio | |
| 02:20 | where this is a ratio of three Is to 200 | |
| 02:27 | . Okay , now we're going along fairly well with | |
| 02:31 | this so hopefully you're not finding it too hard because | |
| 02:34 | it is fairly simple but a few people do you | |
| 02:36 | know , panic when they get these . So the | |
| 02:39 | other thing with ratios is ratios can also be written | |
| 02:41 | as fractions to say we were looking at something like | |
| 02:45 | um Okay , what about seconds and minutes ? Say | |
| 02:49 | I was looking at 17 seconds and I wanted to | |
| 02:51 | compare this to one minute . 1st off . What | |
| 02:56 | you'll notice is to write this as a ratio . | |
| 03:00 | I need to change this . Okay , so I'm | |
| 03:02 | going to change this all in the 2nd 17 seconds | |
| 03:06 | And 60 seconds here . Okay . So we have | |
| 03:10 | a ratio of 17 is to 60 . We can | |
| 03:14 | also write this is 17 Over 60 . We can | |
| 03:19 | write this in a fractional form . Okay . And | |
| 03:21 | that's all that means is but ratios can also be | |
| 03:23 | written in a fractional form . The other thing with | |
| 03:27 | ratios is they can be made into more simple forms | |
| 03:30 | . Okay , this is something we're gonna have a | |
| 03:32 | look at more extensively in another video . So I'll | |
| 03:35 | give you an example that sales were talking about the | |
| 03:37 | amount of kids walking to school . We could say | |
| 03:40 | 20% of kids in a class didn't walk to school | |
| 03:45 | . They got a lift off their parents and 80% | |
| 03:50 | walk to school . So we could write this as | |
| 03:52 | a ratio as 20 To 80 . Okay . And | |
| 03:58 | that's that's fine . We got a ratio there of | |
| 03:59 | 20-80 , but you can actually simplify this further . | |
| 04:02 | You're going to notice that 10 goes into these numbers | |
| 04:05 | . So I could divide 10 into both of these | |
| 04:07 | . All right , Anybody do that divided by 10 | |
| 04:10 | . I would get two is 28 and you might | |
| 04:14 | look at it and go , hey , wait a | |
| 04:15 | second to also goes into this number two goes into | |
| 04:18 | both of these numbers once and four times two goes | |
| 04:23 | into two once and into 84 times . So we | |
| 04:26 | can simplify a ratio and make it more simple . | |
| 04:29 | And you'll notice that this is always four times as | |
| 04:32 | much as this . You know ? This number 84 | |
| 04:34 | times as much as this , number 84 times as | |
| 04:36 | much as two and once . Four times as much | |
| 04:39 | as four there . Okay , so this is just | |
| 04:43 | a simplified version of a ratio . Okay , so | |
| 04:46 | hopefully that helps you a little bit ratios in some | |
| 04:48 | next videos coming up , we will actually be looking | |
| 04:51 | at just how to simplify ratios and that sort of | |
| 04:55 | deal . Okay , see you next time . Bye | |
| 00:0-1 | . |
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