Question

Draw a pie-diagram for the following data of the investment pattern in a five year plan:

Agriculture	Irrigation and Power	Small Industries	Transport	Social service	Miscellaneous
14%	16%	29%	17%	16%	8%

Answer 1

We know:
Central angle of a component = (component value/sum of component values x 360)
Here the total percentage = 100%
Thus, the central angle for each component can be calculated as follows:
 

Item	Amount (in %)	Sector angle
Agriculture	14	14/100 x 360 = 50.4
Irrigation and Power	16	16/100 x 360 = 57.6
Small Industries	29	29/100 x 360 = 104.4
Transport	17	17/100 x 360 = 61.2
Social Service	16	16/100 x 360 = 57.6
Miscellaneous	8	8/100 x 360 = 28.8

Now, the pie chat representing the given data can be constructed by following the steps below:
Step 1 : Draw circle of an appropriate radius.
Step 2 : Draw a vertical radius of the circle drawn in step 1.
Step 3 : Choose the largest central angle. Here the largest central angle is 104.4^o. Draw a sector with the central angle 104.4^o in such a way that one of its radii coincides with the radius drawn in step 2 and another radius is in its counter clockwise direction.
Step 4 : Construct the other sectors representing the other items in the clockwise sense in descending order of magnitudes of their central angles.
​Step 5 : Shade the sectors with different colours and label them as shown in the figure below.​​