Hi, I have this maths homework, where I have been given a set of data and I have to work out the angles to make it all fit into a pie chart. Could someone tell me the equation thingy you have to do?? Thanks in advance :)
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Suppose you have the following data
10
15
30
50
Step one
=======
Add up the total amount of the data
10 + 20+ 30 + 50 = 110
Step Two
=======
Create a fraction of each of them where each part is multiplied by 360 and divided by the total.
10 * 360 / 110 = 33o
20*360 / 110 = 65o
30*360/110 = 98o
50*360/110 = 164
Add the results as a check. It should come to 360
33 + 65 + 98 + 164 = 359 which is about what it should come to.
Step Three
========
Draw your pie chart using these angles. Round your angles to the nearest degree. If you are out 1 or 2 degrees don't worry about it. Protractors are not that accurate anyway. As long as it looks right, it will be OK.
10
15
30
50
Step one
=======
Add up the total amount of the data
10 + 20+ 30 + 50 = 110
Step Two
=======
Create a fraction of each of them where each part is multiplied by 360 and divided by the total.
10 * 360 / 110 = 33o
20*360 / 110 = 65o
30*360/110 = 98o
50*360/110 = 164
Add the results as a check. It should come to 360
33 + 65 + 98 + 164 = 359 which is about what it should come to.
Step Three
========
Draw your pie chart using these angles. Round your angles to the nearest degree. If you are out 1 or 2 degrees don't worry about it. Protractors are not that accurate anyway. As long as it looks right, it will be OK.
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first add all the data up together that you are using in the pie chart
then use the first value in the data, divide that by the total data then multiply by 360
So say you were given three data values such as this:
50, 70, 80
1. add them up 50+80+70 = 200
2. (50/200)x360 = 90
3. Do the same for the other values
(70/200)x360 =126
(80/200)x360 = 144
and the values you obtain are the angles you to make for each data
to make sure add the angles up together and make sure they total up 360
90+126+144 = 360
then use the first value in the data, divide that by the total data then multiply by 360
So say you were given three data values such as this:
50, 70, 80
1. add them up 50+80+70 = 200
2. (50/200)x360 = 90
3. Do the same for the other values
(70/200)x360 =126
(80/200)x360 = 144
and the values you obtain are the angles you to make for each data
to make sure add the angles up together and make sure they total up 360
90+126+144 = 360
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Going around the whole circle, the total angle is 2*pi radians angle or 360 degrees angle. The angle for each piece can be found using the ratio of the datum quantity being the numerator, with the sum of all data being the denominator, times the total angle available, 2*pi radians or 360 degrees.
In terms of areas, the area of a circle is pi*r^2, and the area of a sector is pi*r^2 * (angle in radians)/ 2*pi. [ or pi*r^2 * angle in degrees / 360 degrees ]
In terms of areas, the area of a circle is pi*r^2, and the area of a sector is pi*r^2 * (angle in radians)/ 2*pi. [ or pi*r^2 * angle in degrees / 360 degrees ]
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total population = 100% = 360 degrees
Therefore, 3.6 degrees for each percent.
Or, working directly from the numbers:
population = n
Therefore 360 = n/n
Angle for a result of "k" =
(k/n) * 360
If you have a total of 80 students, and 15 of them are "girls with blonde hair", then that slice of the pie would have an angle of
(15/80) * 360 = 67.5 degrees
Therefore, 3.6 degrees for each percent.
Or, working directly from the numbers:
population = n
Therefore 360 = n/n
Angle for a result of "k" =
(k/n) * 360
If you have a total of 80 students, and 15 of them are "girls with blonde hair", then that slice of the pie would have an angle of
(15/80) * 360 = 67.5 degrees
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Here is a site with multiple links that might help.
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Angle of x = No of x observations/ Total no of observations x 360