Pie Charts

Pie Chart / Pie Graph:

A pie graph (or pie chart) is a specialized graph used in statistics. The independent variable is plotted around a circle in either a clockwise direction or a counterclockwise direction.The dependent variable (usually a percentage) is rendered as an arc whose measure is proportional to the magnitude of the quantity.Each arc is depicted by constructing radial lines from its ends to the center of the circle, creating a wedge-shaped "slice."The independent variable can attain a finite number of discrete values (for example, five).The dependent variable can attain any value from zero to 100 percent.

The illustration is a pie graph depicting the results of a final exam given to a hypothetical class of students.Each grade is denoted by a "slice."The total of the percentages is equal to 100 (this is important; if it were not, the accuracy of the graph would be suspect).The total of the arc measures is equal to 360 degrees.


From this graph, one might gather that the professor for this course was not especially lenient nor severe.It is evident that grading was not done on a "pure curve" (in which case all the arcs would have equal measures of 72 degrees, corresponding to 20%).If this graph were compared with those of classes from other years that received the same test from the same professor, some conclusions might be drawn about intelligence changes among students over the years.If this graph were compared with those of other classes in the same semester who had received the same final exam but who had taken the course from different professors, one might draw conclusions about the relative competence and/or grading whims of the professors.


Directions for questions 1 - 7:

The following pie chart shows the percentage distribution of the expenditure incurred in publishing a book. Study the pie chart and answer the following questions.



Which two expenditures together have a central angle of 108 degree in pie chart ?


If for a edition of a book, the cost of paper is Rs. 56250, then find the promotion cost for this edition ?


If for the certain quantity of books, the publisher has to pay Rs 30,600 as printing cost, then what will be the amount of royalty to be paid for these books ?