my name is Jonathan Hicks today we're drawing pie charts now I'm with this video we're doing pie tales by hand so imagine you're drawing it on a bit of paper I'm going to do another video where you draw pie pie charts using a computer so using Excel in that case so go and watch that one if you want to know how to do it on the computer this video is if you want to draw the pie tails by hand on a bit of paper so using a protractor so that's the semi-circular angle measuring thing now I'm going to assume you know how to use a protractor I'm not going to show you how to use a protractor in this video I'll do another video for how to use a protractor this is how you construct the pie chart how you work out how big each of the wedges should be and then how you go about drawing it on the paper so without further ado I'm going to stick a frequency table up here that we'll need to construct our pie chart so give me a moment all right novio there's our frequency table now I've chosen the question what's your favorite animal so imagine we went round a bunch of people and asked them what their favorite animal was and here are the responses supposedly that they gave so the frequency here tells you the twenty people picked dog is their favorite animal sixteen people went for cats nine one for elephant twenty six for tiger and one person there's always one went for snake now when you construct your pie chart you're going to need a blank column and if you ever has to do this in a test they will give you this blank column here and you use this column to work out the angles of the different segments different wedges within the pie chart need to be so let me just give you a broad picture of what we're aiming at here so pie charts obviously gonna be large circle at some point in the middle and then we're going to construct some wedges to go inside it now the first thing you always drew draw when you draw your pie chart if you need a vertical line that just goes straight up like so and then you're gonna have to work out how much how big each of these wedges are going to be they're going to represent the dog and the cat and the elephant and the different categories so in order to do that the first thing you need to know is how many people you've got altogether so you add up all your frequencies now I have already carefully constructed my frequencies so they should add up to 72 so the total number of people who answered my question air comes to 72 the total angle in the whole circle here or the total angle of the whole circle is always 360 degrees so you've got 360 degrees that you need to share out amongst 72 people the critical thing we need to work out here is how much of an angle how many degrees would each person in here represent once we know that we can work out how big each of the different wedges need to be so in this case you've got 360 degrees and 72 people I want to divide 360 degrees by the 72 so just a stressful do a little calculation bottom here so the angle for one person will be the total number of degrees in this case 360 degrees divided by total number of people at that point you normally reach for your calculator so 360 divided by 72 gives us five so that means you need five degrees for each person in the frequency table yeah so this is 26 people you need 26 lots of five degrees to look at how big the tiger wedge would be so once you've got that once you know that each person is five degrees then you go back to your frequency table and you just multiply each of these frequencies by the five degrees so the dog 20 people went for dog 20 lots of five what 520 is going to give you a hundred hundred degrees so this final column is for working out the angle now usually you just do this on a calculator you can probably just do this in my head but you just times each of these by five because each person is five degrees so nine five is a 45 26 lots of five we can give you a good 30 and one five is five now one little check here to make sure you've done it right is if you add up all the angles you should get 360 degrees because it's got to fill the whole pie chart you can't have a little gap with something missing and if you add those up I think you do get 360 degrees so that's how you work out the angles so just to stress again you take 360 the angle for the whole pie chart divided by the number of people and that tells you how much of an angle how many degrees you need for one person in your frequency table and then that much in this case the five degrees you just multiplied by each of the different frequencies to give you the angles once you know the angles you can start drawing your pie chart now as I say the first thing you do is from the center line draw a line that goes vertically straight up you need a starting point and you always take the straighter point is your starting point and then just work through your different categories so the dog needs to be and I to have an angle of a hundred degrees sorry so from here with your protractor stick protector on measure around a hundred degrees and then draw a line so it'd be here round by a hundred degrees so I'm just going to guess obviously I don't have a giant protractor for this so more or less is going to be about there so I'm saying that that angle there is a hundred degrees now you don't write on the angle like I'm doing here I'm just doing this to explain how to construct it I'll show you what you actually do in a moment but basically you just do going to be drawing the line so you draw that line there and then once you've got that line in this is going to be the dog one you can write dog in here if you want to so next up is the cat that needs to be eighty degrees now this time you start with your protector sitting on this line and you give me imagine around 80 degrees that way so again eighty degrees is going to be about there I'm saying that that wedge is eighty degrees you measure that with your protector so that's going to be the cat elephant next up needs to be 45 degrees so we'll do another one that's going to be about there 45 degrees elephant then we've got the tiger 130 degrees that's a really big one so that's going to go to about there may be so thirty degrees for the tiger and then finally the snake is just five degrees and that should be what's left at this point you check with your protractor put it on here measure that angle make sure that that really is five degrees you might find if you go around this way that it's not quite five you might be out by one or two degrees as long as you're not out by too much it should be fine but you'll find that tiny little errors in measuring each of these angles will sort of add up and give you one or two degrees out by the end if you're more than a couple of degrees out you probably want to rub it out and draw it again but one or two degrees should be fine so this tiny sliver appear it's going to be your last one the snake I can fit that in alright so that's how you construct the pie chart just give me a moment I'm going to rub out these angles in a minute I'm going to show you what you should make it actually look like when you draw it all right so more or less that's what you've done you don't necessarily have to write all the names in like that I have done but that's completely up to you what you really should have though as well as this even if you write the names and you should put a key on it now I strongly recommend for a pie chart you use color makes it look pretty part of everything else but it makes it easier to distinguish their different categories as well so you are you could write the names in like this but even if you do I suggest you have a key at the side if you don't write the names in you absolutely must have a key so the key is going to know this you should write key here to say what it is and your Sencha ly going to have boxes the represent the different colors that you've done on your pie chart so if we pick some colors here so if I say that the dog is going to be red I could color is red like so and then I would do a little red box here at the side and then you right next to that dog and then you do the same thing for the cat so maybe the cats going to be blue and then you do another box here it's blue and you write cat how you carry on like that I won't do all of them you get the idea so you have different colors around here you do the little boxes at the side and right well they are now as I say you don't have to write the names in here because you will have the names on your key but it's very important that you have a key for a pie chart it's the first thing people look at now one very important other thing you do need on your pie chart is a title so generally it refers to the original question from the questionnaire so we ask people what's your favorite animal and you could just write that question at the top or you could give it more of a summary title and you could say something like people's favorite animals something like that it's important that it's descriptive it explains what the chart is about otherwise people will look at this pie chart and they're like okay it's got some intuit animals but I've no idea what so you need the title to explain our case people's favorite animals I see so that's how you can set a pie chart you start with a frequency table work out the angles that are explained you should protractor to draw them in make sure you give it a key and the title