How To Create A Circle Graph

Step 1- Construct a circle using a piece of string, a compass, or you can also trace a circle using any type of circular objects

Step 2- Create the central angles

- A central angle is an angle formed by 2 radii and the vertex of the angle is located at the centre of the circle

Now that you know how to create a circle graph, its time to put your knowledge to the test!!

Here is an example of a set of information we received and had to convert into a circle graph.

Mr. Isfeld surveyed 100 kids on what kind of flavor they liked to eat. 50% of the kids liked If I Had A Million Flavors, 25% liked vanilla, and 25% liked some other flavor.

Construct a circle graph for the following.

• 3 kids use the computer 1-3 days per week.
• 9 kids do not use the computer at all that week.
• 18 kids use the computer 4 or more days on the computer.

Step 1- Find the total number of kids

3+9+18=30

Step 2- Convert the fractions to a percentage

3/30= 1/10= 10/100 = 10%

9/30= 3/10= 30/100 = 30%

18/30= 6/10= 60/100= 60%

There are other methods to turn a fraction into a percentage, but I suggest you to use the method that you are most comfortable with.

Step 3- Convert the percentage to degrees

10% of 360 degrees= 36 degrees

30% of 360 degrees= 108 degrees

60% of 360 degrees= 216 degrees

Use a protractor to measure the central angles for the most accurate results.

If you would want to go in depth about circle graphs. There are some links provide below to help you explore the concept of circle graphs. I recommend you to watch the video and play around with the websites to understand why is that fraction equivalent to that angle and many other questions you may have. If the still can not understand something after exploring the websites and watching the video then you should grab a lunch and talk to Mr. Isfeld about your problem or he is open during the morning and after school too.

Videos:

• http://www.youtube.com/watch?v=ZyikYkjyBT8

Websites:

• http://www.shodor.org/interactivate/activities/PieChart/
• http://nces.ed.gov/nceskids/createagraph/
• http://mathplayground.com/alienangles.html