How To Calculate Pie Charts?


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Katie Harry answered
Pie charts are usually made when the data is present in the form of percentages or fractions. In both cases, it is imperative to remember that the total angle around a point is 360o.
If the question says that one fourth of the clothes were red, two fourths were yellow and one fourth were green. So, you can simply draw a circle and divide it into four equal parts. You should always use a protractor to draw your segments. This is to make sure that all parts (360/4=90) of a pie chart are equal. If the total angle has to be 360, then the angle of one segment would be 90 Then, one part of these would go red and green each and two parts would be for yellow.
Now let's suppose we have a percentage question. Assume that 25% of the people wore slippers, 45% wore boots and the remaining wore pumps. To solve this, we need to find out how much part of the pie chart each option would occupy.
Slippers = 25%
Boots = 45%
Pumps = 100 - (45+25) = 30%

Now multiply each with 360 to find out how large a segment it would have on the pie chart:
25/100 x 360
= 90o
45/100 x 360
= 162o
30/100 x 360 = 108o

We have just obtained the angles which define the segment width for each option. Place your protractor at the center of the circle to start drawing these angles. But before that, make sure that all your options add up to 360 which is what the total sum of all angles around a point should be:
90+162+108 = 360

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