Measurement - Perimeter made easy! - By tecmath
Transcript
00:0-1 | Good day and welcome to take Math Channel . What | |
00:02 | we're gonna be having a look at in this video | |
00:03 | is a really quick video . Looking at the concept | |
00:05 | of perimeter , uh the perimeter , the distance around | |
00:09 | the outside of the shape . Okay , so without | |
00:12 | much further ado let's just launch straight into it . | |
00:14 | So , say you were asked to work out the | |
00:15 | perimeter of this shape ? Yeah . Ok . And | |
00:19 | I'll draw on for you right now , a lovely | |
00:21 | little rectangle , fairly rough one . But it will | |
00:25 | suffice to say . I asked you to work at | |
00:28 | the perimeter of this on this side here Measured up | |
00:30 | and it was five cm and this site here was | |
00:34 | three cm . So the way that you would go | |
00:37 | to work at the perimeter is we want to work | |
00:39 | at the distance around the outside of the shape . | |
00:43 | Okay , so the total distance to this side plus | |
00:45 | this side , this side , this side . So | |
00:48 | the first step is you put on the unknown side | |
00:51 | . So we have this side here . Right now | |
00:53 | we have this site here written down but there's two | |
00:55 | sides . We don't know but it's fairly simple because | |
00:58 | a rectangle we're going to see here . This length | |
01:01 | is here is the same as this length here . | |
01:03 | So this is 5cm And this length here is the | |
01:08 | same length as this length here . So this is | |
01:11 | three cm and the perimeter . So the perimeter is | |
01:18 | the total distance around the outside . So it equals | |
01:23 | as follows . Articles . Usually what I do is | |
01:26 | I'd actually by on this and I've had in a | |
01:29 | particular direction . I'd like to head in a clockwise | |
01:32 | direction when I do this but it's really really worth | |
01:34 | marking . On First off we have five sentiments plus | |
01:42 | three . Sina means plus five centimeters plus three centimeters | |
01:52 | . Okay , this is all centimeters five plus three | |
01:55 | plus five past three . Then we get the answer | |
01:59 | of five right 13 16 and this is in centimeters | |
02:06 | really important for that unit . And that's how you | |
02:09 | work out the perimeter . Just add them up . | |
02:11 | Really good little hit though to mark on where you | |
02:13 | started and you're possibly if you get really stuck with | |
02:16 | mark on the lines issue are adding them . Anyway | |
02:20 | . What about we do a different type of shape | |
02:25 | . Let's work out the perimeter of the following . | |
02:28 | Um So what about I do this shape here , | |
02:32 | which is a tropical . Yeah . Okay . Now | |
02:40 | put some distance is on this . This side here | |
02:43 | is seven centimetres . This one here I'm going to | |
02:48 | use a bit of a nasty one . I'm going | |
02:49 | to Change this 1-7 35 millimeters . And this one | |
02:58 | here is for centimeters we have all the sides here | |
03:02 | . Now you'll notice this but we have a problem | |
03:06 | . And this is this . we actually have a | |
03:08 | using centimeters in a couple of our measurements and millimeters | |
03:11 | in one . So the second step after getting all | |
03:14 | the side length is making sure all the units are | |
03:17 | the same type . So this should be in centimeters | |
03:21 | . What you might remember from other videos were made | |
03:24 | , is that one cm is 10 millimeters . Okay | |
03:33 | , so that's what it's equal to . So You | |
03:36 | might even have that little table the way we work | |
03:38 | that out , a little diagram . But literally what | |
03:40 | we're gonna have to do is we're going to divide | |
03:42 | this answer by 10 . So this becomes We're gonna | |
03:46 | get rid of that there and this is going to | |
03:48 | become seven 0.5 centimeters . Okay , so the perimeter | |
03:56 | is gonna be just all these sides added together . | |
03:59 | So start in there and I'm gonna go in this | |
04:02 | clockwise direction . So I'm gonna add 7 7.54 . | |
04:07 | So the perimeter equals seven boss 7.5 boss 454 And | |
04:22 | we add these together . This is all going man | |
04:24 | centimeters seven plus 7.5 is 14.5 plus 4 , 18 | |
04:33 | 0.5 cinnamon . Okay , how did you go with | |
04:39 | that now ? What's gonna put one last shape up | |
04:41 | here and it's going to be a bit more of | |
04:43 | a difficult shape this time . So the shape we're | |
04:48 | going to put up is it's not going to be | |
04:50 | too difficult . I won't make it too crazy , | |
04:53 | but it's going to look like this . Okay . | |
05:03 | And I put the sides on these . Yeah , | |
05:06 | I put some sides on that unknown . Just a | |
05:09 | various . Because this is another type of problem you | |
05:12 | might have given . So say this one here is | |
05:15 | seven centimetres . This one here is all right , | |
05:21 | that All right out like this is seven cm . | |
05:25 | This one here is Uh huh . three cm . | |
05:29 | I'm sorry . This is not the scale . This | |
05:31 | one here is four centimeters . This one here is | |
05:39 | six centimeters . And you were given this to work | |
05:42 | out the perimeter . Now first off , what we | |
05:45 | do is we make sure all sides , Right ? | |
05:48 | So we have his side . We have this side | |
05:52 | , we don't have this side . So it's worth | |
05:53 | mark here sort of go around and check that you | |
05:56 | have and so you have this one , you don't | |
05:57 | know this . Once in a market , this one | |
05:59 | we have this one we have is what we don't | |
06:01 | see the market and this one we do have . | |
06:03 | Okay , so let's work out the ones we don't | |
06:06 | know . Yeah , there's a bit of a trick | |
06:09 | for doing this . And first off , we want | |
06:11 | to know this one here from here to hear . | |
06:15 | So the way that we do this is as follows | |
06:17 | , we know that from here to here is seven | |
06:21 | and from here to here is six . So this | |
06:25 | word is one more centimeter than this one here . | |
06:30 | This extra bit would total the distance . So this | |
06:33 | one here plus this one here would be a good | |
06:35 | seven . So this +16 so it makes this one | |
06:38 | here one centimeter . Okay , we have this other | |
06:43 | one down here , Okay ? And we know that | |
06:46 | this one is as big as three and four centimeters | |
06:49 | put together . So this one seven centimetres So now | |
06:53 | we have all our sides we can add them , | |
06:55 | they're all the same unit . So everything's good there | |
06:58 | . Let's work out the perimeter so to start here | |
07:01 | and I'm just gonna basically jot them down as I | |
07:05 | see them . So we're equals three plus one plus | |
07:10 | 46 By seven x 7 . So we're gonna be | |
07:15 | adding all of these that's all going to be in | |
07:21 | centimeters . Okay , so three plus one is four | |
07:25 | Plus four is 8 plus six is 14 Plus seven | |
07:31 | is 21 plus seven . Pickles . 25 said to | |
07:38 | me . So how'd you go with those ? Hopefully | |
07:41 | you're pretty good with the idea of perimeter . So | |
07:43 | perimeter , just the distance around the outside and there's | |
07:45 | just a few little tricks that I've given you there | |
07:48 | of things you might get asked when you're asked to | |
07:50 | work out perimeter . I hope there was some help | |
07:53 | . Thanks a lot for the next one . |
Summarizer
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Measurement - Perimeter made easy! is a free educational video by tecmath.
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