How to construct a Pie Graph (pp24-25 Crossroads)
First pie graph: Number of families per income group (class)
A: Get your percentages first:
1.
2.
3.
4.
Total number of families: 1029, 586
Upper class: 26, 586
Middle class: 154, 000
Lower class: 849, 000
Calculations – step 1:
1. Upper class: 26, 586 divided by 1029, 586 multiplied by 100 = 2.6%
2. Middle class: 154,000 divided by 1029, 586 multiplied by 100 = 15%
3. Lower class: 849, 000 divided by 1029, 586 multiplied by 100 = 82.4%
B: Making the pie graph – Calculations – step 2:
Multiply each % by 3.6 to obtain the number of degrees:
1. 2.6 x 3.6 = 9.36 degrees or 9 degrees rounded to the nearest whole number
2. 15 x 3.6 = 54 degrees
3. 82.4 x 3.6 = 296.6 or 297 degrees rounded to the nearest whole number
297 + 54 + 9 = 360 (degrees) or a full circle
C: Drawing the pie graph
Easiest way is to use or download an image from the internet of a
Draw a circle and using
the guide draw a pie
section of 63 degrees (9
plus 54) and divide again
to create the line for 9
degrees.
The remainder is 297.
Label all three sections.
protractor