Pie Charts

Time for some statistics, then.

Pie charts.
What are they?
They're circles with petty colors.
No.
Pie charts are useful for demonstrating parts and percentages in relation to the whole. Here's an example of a pie chart (and please excuse the badly drawn circle.)

Note that you can't really take any information from this, because we don't have any labels on here.
Let's change that.

Here's a pie chart now saying what most writers do when they say they're writing (using a graph with a better drawn circle)...

Now this graph, you can get some information out of. Not only can you see that most authors spend way too much time looking at writing websites and social networking, but that, compared with the whole, it's pretty huge.
But how can you tell exactly what these percentages are?
for example...
What if you had this pie chart?

You can still see that the majority of authors spend too much time online- but you can't tell how much, exactly.
So, how do you find that out?
With your protractor!

Measure the angles of the pie chart, and you'll get something like this...

Now we have the angles of the different sections! But how do we figure out anything else, then? With a series of mathematical problems (duh).

To figure out the percentage of these, you simply put the angle over 360 (total angle of a circle). For example, here's one of them worked out.




Take 43.2 and use long division to transform it into .12 (360 goes into 432 one time, remainder of 72. Drop the zero. 360 goes into 720 two imes, no remainder). Then move the decimal place two points to the right, and add a percentage sign.

 Therefore, an angle of 43.2 means 12%. If you do that same thing with the rest of the different angles, you'll get the chart we previously had.
But what if you want to figure out exactly how many people did each?

Well, first of all, you need to either figure out how many is in one sector, OR you need to figure out how many people there are as a total.
Let's use the first one for an example.

Let's say for a minute that the percentage of authors who actually write when they say they're writing (12%) equals 20 authors.

Now that you know that 12% = 20 people, you can figure out what the whole is- and from there you can figure out what the different sectors are!
The easiest way (I've found) to do this is to simply divide the amount of people by the percentage, making it into a fraction, and then multiplying that by 360.
(Easier than it sounds)
Let's take a look at that.

20 and 12 are both divisible by 2. Dividing them both equals 10 over 6. To make 360 into a fraction, you put it over 1. 360 and 6 are both divisible by 6. 6 divided by 6 equals 1 (making 10/6 into 10/1, or an even number of 10), and 360 divided by 6 equals 60 (making 360/1 into 60/1). Therefore, 20/12 x 360/1 = 10 x 60 = 600 = total amount of authors.

Now that we have 600 as the total amount of people in this pie chart, we can figure out what the other sections are.
This leads into the next part.
...How in the world do you figure out what amount of people per sector there are if you have the total amount and the angles of the parts?!
What do you do?!
Okay. Let's look at our pie chart (with the angles) again.

Now, we know that the total amount of people is 600.

But how do we figure out, say, the amount of people who do nothing when attempting to write? (Aka- staring blankly at their computer screen for hours).

First of all, you have to take the angle of the sector and put it over 360. Then multiply that by the total amount. The number you get will tell you how many people per sector there are.

Allow me to demonstrate.



360 and 600 are both divisible by 60. 360 divided by 60 equals 6. 600 divided by 60 equals ten. Therefore 46.8/360 x 600/1 = 46.8/6 x 10/1. 10 and 6 are both divisible by 2. Divide both. You get 46.8/3 x 5/1. Divide 46.8 by 3 using long division. 3 goes into 4 one time, remainder of 1. Bring down the 6. 3 goes into 16, 5 times, with a remainder of 1. Bring down the 8. 3 goes into 18, 3 times, with a remainder of 0. That gives you 15.6 x 5. Multiply them. You get 78 (after multiplication you move the decimal the total amount of places in the two numbers- in this case, one. That turns 780 into 78.0, or 78.) Therefore 46.8/360 x 600/1 = 78.



After that, you can see that the answer is 78- that is, there are 78 authors who, when saying that they're going to write, just sit there and stare at a blank page instead. XD

To draw a pie chart, it's quite easy. Start with a circle.

Draw the radius.

From this, measure your first angle. (In this graph's case, 90 degrees).

Then the next angle (in this case, 12 degrees)(and please note I'm sort of estimating on this... Not really measuring. XD)

Then the next one... and the next one... and the next one... Always measuring from the line right next to the sector.

Ta da! Pie chart. Then you can figure out the percentages, if you want, or just color it, and add your labels... Whatever floats your boat (and satisfies your math exercise/problem... xD).