back to Unit 12

Constructing Circle Graphs

When data are expressed as parts of a whole, you can display the data in a circle graph.  The entire circle represents 100% of the data.  The different parts are represented as sectors of the circle.  since there are 360 in a circle, the sum of the central angles formed by the sectors must be 360

Example:  Draw a circle graph to represent the following data.  In a survey, 350 people named their favorite movie:

          Star Wars,  119

          Indiana Jones and the Temple of Doom,  98

          Gone with the Wind, 77

          White Christmas,  56


Step 1: Find the decimal for each part of the whole. The whole in this case is 350 (all the people surveyed)

    Star Wars:                                                Gone with the Wind:


    Indiana Jones:                                      White Christmas:   


Step 2: Find the measure of each films central angle (What part of the circle they should be drawn)         

       Star Wars:  .34 360 = 122.4  round to 122
       Indiana Jones: .28   360 = 100.8  round to 101
       Gone With the Wind: .22   360 = 79.2  round to 79
       White Christmas: .16   360 = 58  round to 58