Example

Students at a high school were asked to pick their favorite instrument. The table below shows the number of students who chose each instrument. Draw a circle graph for the data.

• Step 1 Add to find the total number.

  35 + 103 + 150 + 182 = 470 35 plus 103 plus 150 plus 182 equals 470

• Step 2 For each central angle, set up a proportion to find the measure.

  Use a calculator to solve each proportion.

  35 470 = a 360 ° 103 470 = b 360 ° 150 470 = c 360 ° 182 470 = d 360 ° a ≈ 27 ° b ≈ 79 ° c ≈ 115 ° d ≈ 139 ° table with 2 rows and 8 columns , row1 column 1 , 35 over 470 , column 2 equals . fraction eh , over 360 degrees end fraction , column 3 103 over 470 , column 4 equals . fraction b , over 360 degrees end fraction , column 5 150 over 470 , column 6 equals . fraction c , over 360 degrees end fraction , column 7 182 over 470 , column 8 equals . fraction d , over 360 degrees end fraction , row2 column 1 , eh , column 2 almost equal to 27 degrees , column 3 b , column 4 almost equal to 79 degrees , column 5 c , column 6 almost equal to 115 degrees , column 7 d , column 8 almost equal to 139 degrees , end table

• Step 3 Use a compass to draw a circle. Draw the approximate central angles using a protractor.

  
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• Step 4 Label each sector.

  
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  Favorite Musical Instruments