hey guys so this is a really important lesson it has to do with scales now you've probably seen it you know when they give you a map for example so here's a big map and then at the bottom here they've got something like one to ten thousand okay this is what we're going to be talking about in this lesson we're going to be doing quite a few calculations measuring all sorts of interesting things specifically we're going to be looking at three different ways that they can ask you this the first one is um they'll give you the scale and then you need to find the distance the real world distance okay I'm not going to mention too much of this it's going to confuse you but we're going to get to that as we go along so let's start with part one where they're going to give us a scale and then we need to find the real world distance now when I show you the next example before you try to do anything by yourself you need to listen to something very important that I need to tell you my advice is that you don't try to do this by yourself because what happens is that this one to fifty thousand I made that up and that only works based on the exact dimensions and the zoom that I've got on my laptop so if you watch this on a cell phone or a laptop screen that's different to me it's not gonna work because you're going to take your ruler and you're going to measure a longer distance or a shorter distance depending on if you are on a different laptop or if you're on a different uh um like a cell phone because you can see that it can zoom up so for example if I'm zoomed like that and I want to measure the distance from there to there then if I had to zoom in cool let's quickly just measure that with a ruler then it's going to look like it'll be about five centimeters but if I had to then zoom in then all of a sudden we can see that instead of five centimeters now it's like nearly or it's pretty much nearly six centimeters so the zoom has a big impact on all of this that's why you can't try to do this um on your cell phone or on your laptop and expect to get the same answer as me so my advice is rather just watch How I do it and then when you are in an exam or if you have a practice map next to you whatever they give you in the exam it'll be the same Zoom for everyone and so then it will work you're not gonna one of you gonna be doing it on your cell phone and the other one on your laptop no you're gonna have a map in front of you and the zoom is going to be the same for all of them okay so yeah go and try to get the same answer as me um just watch what I'm doing and make sure you understand okay so we spoke about the zoom that's really important now determine the straight line distance from Golden Acre to poverlay by the way this is actually an area where I live um who I currently live maybe in when when you're watching this in the future I might be living in like Egypt I don't know but who knows um but at this present moment um when I'm recording this I live in an area called Somerset West and went to a school called pavile and is watching this right now yep I went to poverle so it says um determine the straight line distance from Golden Acre okay so Golden Acre is over there to povole okay so um remember there's these little gray dots that's where you start because some of you are like Paul villain you don't know where to start you start in the middle no no you start at the gray part over there and then the gray part over there okay now they saying the straight line distance okay so he's gonna go get a ruler and just do a straight line so let's go get our ruler okay now because my ruler is already on the page I can zoom now and that won't change anything because my map and my ruler are both zooming at the same scale so you see how it's going from zero to just a little bit more than four now if I zoom in it still stays like that because the map and the ruler were already fixed on each other so by me zooming in there's not a problem so I can zoom in just to get a bit of a view now can you see that it's going you've got to look in the middle of the gray Circle so it's about four point it's between 4.2 and 4.3 so in a test they'll give you a range that you're allowed to get but I'm gonna say uh four point two okay 4.2 but as I said in a test they'll give you a range where your answer is allowed to be okay so that is 4.2 centimeters okay so the map length is 4.2 centimeters so okay now we need to try to figure out how far is that in real life because you're definitely not going to walk 4.2 centimeters um I live in this area and I can tell you that it's probably over a kilometer away so it's definitely not 4.2 centimeters imagine that's how far you walk that's literally like not even a foot like it's tiny okay so obviously that is the map length that is not the map that is not the length in real life so that's where we're going to start using our scale so what it tells us is that the map this is your map and then this is your real life so it says that a one on the map actually means 50 000 in real life so the real life is much larger it's fifty thousand more fifty thousand times more so if your map length is 4.2 centimeters then your real length will be 4.2 multiplied by 50 000 right because for every one then it's 50 000 times more so you multiply by fifty thousand and that'll give you 210 000 centimeters now I should have said here let's work it out in kilometers because yeah you're not going to tell someone hey bro you want to come to my house no it's not far it's 210 000 centimeters away I promise you that person's gonna think something's wrong with you um it's just a bit weird okay uh centimeters okay so now we're going to convert Now Kevin how do we convert from centimeters to kilometers ah well remember a few chapters ago we looked at conversions and we looked at volume mass distance remember when I showed you that the main lengths or distances that we use is kilometers meters centimeters and millimeters and we said kilometers is always on the left then this one then this one then this one and what we said is that the numbers in between would be a thousand then a hundred and then ten and what we've learned is that when you go this way you multiply when you go this way you divide remember that I so what we want to do now is we want to convert the centimeter length into kilometers okay so we're going to go to the left we're going left so when you go left you divide so we're going to say two hundred and ten thousand divide by 100. and then divide by 1000 remember you divide by all the numbers that you pass and so if you had to work this out you end up with 2.1 kilometers now that makes sense that's um I mean not everyone watching this lives in some situations of course probably hardly any of you but um you know if you're living in a little town 2.1 kilometers seems about right whereas mentioning two hundred and ten thousand sounds a bit weird and it wouldn't be this one this is just your map length let's do another example okay so this will be our last example remember I said we're gonna do a part one part two and a part three remember in the beginning uh let me just show you um we said yeah but I'm gonna split them up so part one will be this lesson and then part two and part three will come up in the future lessons so here they want us to determine the straight line distance from hold of you okay so hold a view is over there all the way to erinville estate okay so remember to use the little gray circles so it's from there to there so let's go get our ruler okay so I couldn't get the ruler to rotate perfectly but you can see here that I've got um hold of you and then um erinville estate ideally I would have wanted my ruler to go through the middle of here but that's okay this is just for practice so I'm gonna zoom in now and if we had to read off the the length it's gonna be um so there's 13 and 14 so it's in between so it's going to be 13.7 13.7 make sure you agree with me on that 13.7 now that is not the real that's just on the map that's just on the map so map will be 13.7 centimeters now we know that one on the map is 50 000 times larger in real life remember real life is always bigger than on a map maps or maps have to be very small um for example that could be a house over there but in real life that house is really really big or much bigger than that I mean not even an ant would live that so what we now do is to get the real we say 13.7 multiplied by 50 000 and that'll give us 685 000. centimeters but now we want to give our answer in kilometers so remember we have kilometers meters centimeters and millimeters and in between here we have a thousand a hundred and ten when you go this way you multiply when you go this way you divide and so what we'll do is we'll just say 685 000 so we're going from centimeters to kilometers so we're going to the left so we will divide and we'll divide by a hundred and then we'll divide by a thousand so we're going to say divide by a hundred and then divide by a thousand and that'll give us 6.85 kilometers so there we have it and then in the next lesson we will go to part two where we modify it a little bit and they ask us something different and then in part three they'll do something a little bit different