Pie Charts: Practice Problems Grade 7
A
pie chart
(also called a Pie Graph or Circle Graph) makes use of sectors in a
circle. The angle of a sector is proportional to the frequency of the data.
The formula to determine the angle of a sector is:
���������� ���� ������������
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× ������
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Study the following steps of constructing a circle graph:
Step 1 :
Calculate the angle of each sector, using the formula
Step 2
: Draw a circle using a pair of compasses
Step 3
: Use a protractor to draw the angle for each sector.
Step 4 :
Label the circle graph and all its sectors.
Example:
In a school, there are 750 students in Year1, 420 students in Year 2 and 630
students in Year 3. Draw a circle graph to represent the numbers of students in
these groups.
Solution:
Total number of students = ������ + ������ + ������ = ��, ������.
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