Question

The following table shows how a student spends his pocket money during the course of a month. Represent it by a pie-diagram.

Items	Food	Entertainment	Other expenditure	Savings
Expenditure	40%	25%	20%	15%

Answer 1

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

Item	Expenditure (in %)	Sector angles
Food	40	40/100 $\times$ 360 = 144
Entertainment	25	25/100 $\times$ 360 = 90
Other expenditures	20	20/100 $\times$ 360 = 72
Savings	15	15/100 $\times$ 360 = 54

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 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 as in figure below.​​