Pre-Algebra: Chapter 11-2
Making Circle Graphs
We need a few things to make circle graphs!
- Something to trace out a circle with, a glass, coffee cup …. nothing freehand is ACCEPTED.
- A protractor to measure degrees with.
- A calculator to convert numbers (ratios) to percentages.
The steps
Make a circle and mark the center
Draw a diameter
- Figure out how large each “pizza slice” should be by counting the number “out of”. An example is 14 people liked chocolate out of a total of 24 people
- Convert the ratio (14/24) to a decimal (0.5833) and percentage (58.33%)
- Use that percentage and multiply it by the 360° in a circle. (58.33% x 360 on a calculator if your have a percentage key OR 0.5833 x 360 by hand).
- That new number (in our case 210°) is the measurement in degrees that the “slice” has to be. Use your protractor to measure the arc from ONE side of the diameter.
Complete the above steps for the remainder of the circle graph! You may need or want to erase the other part of the diameter once you have started adding new pieces of the pie.
Algebra: Chapter 11 TEST
Let’s hope we all did well!!