The pie-chart or a pie-graph is a method of representing a given numerical data in the form of sectors of a circle.
The sectors of the circle are constructed in such a way that the area of each sector is proportional to the corresponding value of the component of the data. From geometry, we know that the area of the sector of a circle is proportional to the central angle.
So, the central angle of each sector must be proportional to the corresponding value of the component.
Since the sum of all the central angles is 360°, we have
Central angle of the component =((Value of the component/Total value) X 360) o