Question

Draw a pie-diagram for the following data of expenditure pattern in a family:

Items	Food	Clothing	Rent	Education	Unforeseen events	Midicine
Expenditure (in percent)	40%	20%	10%	10%	15%	5%

Answer 1

We know:
Central angle of a component = (component value/sum of component values $\times$ 360^ο)
Here, the total % of items = 100
Thus, central angle for each component can be calculated as follows:

Item	Expenditure	Sector angle
Food	40%	40/100 $\times$ 360 = 144
Clothing	20%	20/100 $\times$ 360 = 72
Rent	10%	10/100 $\times$ 360 = 36
Education	10%	10/100 $\times$ 360 = 36
Unforeseen events	15%	15/100 $\times$ 360 = 54
Medicine	5%	5/100 $\times$ 360 = 18

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 144^o. Draw a sector with the central angle 144^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 other sectors representing 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 as in figure below.​​