I hope you understand this brief tutorial, although it's best done with visual aid!

Let's start with sample data.
Garri  -  80bags
Rice  -  45bags
Beans - 35bags
Cocoyam  -  20bags
(The above information represent the amount (in bags) of crops produced by a farmer in 2013; represent the information on a pie chart.)

Pie charts are actually like percentages. In percentages, you talk about per cent, i.e. out of 100, but in pie charts, it is out of a certain totalled amount, and then 360.
Oh! let's see how.

How many bags in total?
Yes, 180 bags - 80 + 45 + 35 + 20 = 180

Now, represent each good as a fraction of the whole, 180.

Garri = \frac{80}{180}
Rice = \frac{45}{180}
Beans = \frac{35}{180}
Cocoyam = = \frac{20}{180}

Then, represent each as a part of a whole circle, 360.

Garri = \frac{(80)(360)}{180} = 160°
Rice = \frac{(45)(360)}{180} = 90°
Beans = \frac{(35)(360)}{180} = 70°
Cocoyam = \frac{(20)(360)}{180} = 40°

Did you check to see if 160° + 90° + 70° + 40° = 360°?

1. Use a pair of compass to draw a circle.
2. Starting from the centre, draw a line to touch the circumference at any point.
3. Place your protractor on that line and mark off 160° on your protractor.
4. Remove the protractor and use a ruler to draw a line from that mark to the centre.
5. Place the protractor again on the new line and mark off 90°.
6. Remove the protractor again and draw a line from the new mark to the centre.
7. Repeat steps 5 and 6 for angles 70° and 40° as you go round the circle.
8. Note that your last line is already marked because it was your starting point.
9. Label all the portions.
10. Sit back and marvel and your newly acquired steering! :D

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