Tutorial on how to read and interpret pie charts.
Example 1:
The pie chart below shows the percentages of blood types for a group of 200 people.
a) How many people, in this group, have blood type AB?
b) How many people, in this group, do not have blood type O?
c) How many people, in this group, have blood types A or B?
Solution to Example 1:
a) 19% * 200 = 19 * 200 / 100 = 38 people
b) (100%  40%) * 200 = 60 * 200 / 100 = 120 people
c) (16% + 25%) * 200 = 41 * 200 / 100 = 82
Example 2:
The pie chart below shows the percentages of types of transportation used by 800 students to come to school.
a) How many students, in the school, come to school by bicycle?
b) How many students do not walk to school?
c) How many students come to school by bus or in a car?
Solution to Example 2:
a) 45% * 800 = 360 students
b) (100%  15%) * 800 = 680 students
c) (30% + 10%) * 800 = 320 students
Example 3:
The pie chart below shows the percentages of the world population in each continent. The present world population is about 7 billion.
a) How many people live in Africa?
b) How many people do not live in Asia than?
c) How many more people live in North America than in South America?
Solution to Example 3:
a) 15% * 7 = 1.05 billion
b) 7  60.4% * 7 = 2.772 billion
c) (7.3%  6%) * 7 = 91 million
Example 4:
The total area of Asia, Africa, North America, South America, Europe and Australia is 134 million square kilometers. The pie chart below shows the percentages of each continent.
a) What is the area of Asia?
b) What is the area Europe?
c) How much bigger is Africa than Europe?
Solution to Example 4:
a) 33.2% * 134 = 44.5 million square kilometers
b) 7.5% * 134 = 10.5 million square kilometers
c) (22.3%  7.5%) * 134 = 19.8 million square kilometers
More references on elementary statistics and probabilities.
