Pie chart

Example 3

The survey about pupils interests in subjects is as follows: 30 pupils prefer English, 40 pupils refer French and 50 pupils prefer Kiswahili. Show this information in a pie chart.

Step 1: put all you are data into a table and then add up to get a total.

Preferred Subjects
English	French	Kiswahili	Total
30	40	50	120

Step 2: divide each value by the total and then multiply by 360 degrees to figure out how many degrees for each "pie slice" (we call pie slice a sector) We multiply by 360 degrees because a full circle

Preferred subjects
English	French	Kiswahili	Total
30	40	50	120
$\frac{30}{120} \times 360 = 90$	$\frac{40}{120} \times 360 = 120$	$\frac{50}{120} \times 360 = 150$	360

Step all information required. Use a protractor to measure degrees of each sector. It will look like the one here below:

Example 4

Interpreting the pie charts.

How many pupils are between 121-130cm tall? The angle of this section is 36 degrees. The question says there are 30 pupils in the class. So the number of pupils of height 121 - 130 cm is:

$\frac{36}{360} \times 30 = 3$