Circle Graphs Make and Analyze

Why do we have circle graphs? A circle graph is used to compare data that are parts of a whole. The pie-shaped sections show the groups. The percents add up to 100%

Make a circle graph The table shows the time Mike spends studying each subject during homework time. Follow these steps to sketch a circle graph of the data. Mike’s Homework SubjectPercent math50% social studies15% reading25% science10%

Step 1: Write each percent as a fraction. Mike’s Homework SubjectPercent = Fraction math50% = 50/100 = 1/2 Social studies15% = 15/100 = 3/20 reading25% = 25/100 = 1/4 science10% = 10/100 = 1/10

Step 2: Draw a circle. Since 50% = 1/2, shade and label ½ of the circle for math. Math 50%

Step 3 Since 25% =1/4, shade and label 1/4 of the circle for reading. Math 50% Reading 25%

Split the remaining section so that one section is slightly larger than the other. Label the slightly larger section social studies for 15%, and the smaller one science for 10%. Step4: Math 50% Reading 25% Science 10% Social Studies 15%

Analyze a circle graph In the circle graph to the right, how does the amount of time Mike spends studying math compare to the amount of time he studies reading? The section representing math is twice the size of the section representing reading. So, Mike spends twice as much time studying math as reading. Math 50% Reading 25% Science 10% Social Studies 15%

Your turn… 1. Sketch a circle graph of the data from the table. 2. In your circle graph, which two sections represent the responses by the same amount of students? 3. In your circle graph, how does the number of students that chose blue compare to the number of students that chose purple? Favorite Color ColorPercent blue33% Red25% Green25% Purple10% yellow7%