Pie Chart

A pie chart can used to compare the relation between the whole and its components. A pie chart is a circular diagram and the area of the sector of a circle is used in a pie chart. Circles are drawn with radii proportional to the square root of the quantities because the area of a circle is $$\pi {r^2}$$.

To construct a pie chart (sector diagram), we draw a circle with radius (square root of the total). The total angle of the circle is $${360^ \circ }$$. The  angles of each component are calculated by the formula.

\[ Angle\,of\,Sector = \frac{{{\text{Component Part}}}}{{{\text{Total}}}} \times {360^ \circ } \]

These angles are made in the circle by means of a protractor to show different components. The arrangement of the sectors is usually anti-clock wise.

 

Example:

The following table gives the details of monthly budget of a family. Represent these figures by a suitable diagram.

Item of Expenditure
Family Budget
Food
$$\$ {\text{ 600}}$$
Clothing
$$\$ {\text{ 100}}$$
House Rent
$$\$ {\text{ 400}}$$
Fuel and Lighting
$$\$ {\text{ 100}}$$
Miscellaneous
$$\$ {\text{ 300}}$$
Total
$$\$ {\text{ 1500}}$$

Solution:

The necessary computations are given below:

\[ Angle\,of\,Sector = \frac{{{\text{Component Part}}}}{{{\text{Total}}}} \times {360^ \circ } \]

 

Items
Family Budget
Expenditure $
Angle of Sectors
Cumulative Angle
Food
$$600$$
$${144^ \circ }$$
$${144^ \circ }$$
Clothing
$$100$$
$${24^ \circ }$$
$${168^ \circ }$$
House Rent
$$400$$
$${96^ \circ }$$
$${264^ \circ }$$
Fuel and Lighting
$$100$$
$${24^ \circ }$$
$${288^ \circ }$$
Miscellaneous
$$300$$
$${72^ \circ }$$
$${360^ \circ }$$
Total
$$1500$$
$${360^ \circ }$$

 

Pie Chart

Pie Chart