Pie Chart

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

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.

These angles are made in the circle by mean 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:

 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