Video Ten: Constructing Circle Graph: Part 1

Key Ideas:

Circle graph - shows how the parts of a set of data compare with the whole set of data

Here is an example to work through and try!!

Example:  I asked 100 people what is your favorite color. 

To draw a circle graph:

Step 1:  Create a table like the one below (if it is not already given to you). 

Step 2: Write each number as a fraction of the sum of the numbers in the data

• 20 out of 100 people like Red so this fraction would be 
• Blue the fraction is 
• Green the fraction is 

Step 3: Write each fraction as a percent (this is easy for this example since the denominator is already 100)

• Red is 20%
• Blue is 45%
• Green is 35%

Step 4: Write each fraction as a decimal, then multiply by 360^o to find the size of each angle needed for the sectors 

• Size of angle for Red is 0.20 x 360^o = 72^o
• Size of angle for Blue is 0.45 x 360^o = 162^o
• Size of angle for Green is 0.35 x 360^o = 126⁰

Step 5: Use your protractor to draw the angles in a circle like the one below.  You can either draw your own circle or your teacher can provide you with a copy of it.  Start by drawing the radius of this circle.  Try it on your own!  If you need help see your teacher the next class.

NOTE: GO BACK TO REVIEW HOW TO USE A PROTRACTOR AT THE BEGINNING OF THIS UNIT (VIDEO 1)