Pie Charts & Basic Probability explained through a friendly whiteboard conversation, examples, visuals, and practice for school students.
Step 1
Notes
Step 2
Formulae
Step 3
Examples
Step 4
Practice
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Pie charts and probability both use parts of a whole.
A pie chart shows data as sectors of a circle. Probability tells how likely an event is.
These ideas are used in surveys, games, weather reports, and simple predictions.
A pie chart is a circle divided into sectors. Each sector shows part of the total data.
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Probability measures chance. An outcome is one possible result. An event is a result or group of results we are interested in.
When all outcomes are equally likely, probability is found by dividing favourable outcomes by total outcomes.
Meaning: A pie chart shows parts of a total using a circle.
Definition: A pie chart is a circular graph divided into sectors.
If half the class chooses football, football takes half the circle.
Meaning: A central angle is the angle of a sector at the centre of the circle.
Definition: Central anglategory valuotal value x 360 degrees.
If 10 out of 40 students choose chess, angl x degrees.
Meaning: An outcome is one result. An event is the result we want.
Definition: An event is a set of favourable outcomes.
When rolling a die, getting 4 is an outcome. Getting an even number is an event with outcomes 2, 4, and 6.
Meaning: Probability tells how likely something is.
Definition: For equally likely outcomes, probabilitavourable outcomeotal outcomes.
For a fair die, the probability of an even number is .
Easy
Question: A fair coin is tossed once. Find the probability of getting heads.
Medium
Question: A die is rolled once. Find the probability of getting a number greater than 4.
Exam-level
Question: In a survey of 60 students, 15 choose music. Find the central angle for music in a pie chart.
Using 100 instead of 360 for pie chart angles
Why it happens: Students confuse percentages and angles.
Correct approach: Use 360 degrees for central angles in a pie chart.
Counting only favourable outcomes
Why it happens: The total sample space is skipped.
Correct approach: List all possible outcomes before finding probability.
Writing probability greater than 1
Why it happens: Favourable and total outcomes are swapped.
Correct approach: Put favourable outcomes over total outcomes.
Why is a full pie chart 360 degrees?
A pie chart is a circle, and one full circle has 360 degrees.
Can probability be written as a decimal?
Yes, but a fraction is often clearer in basic probability.
What does equally likely mean?
Equally likely means each outcome has the same chance of happening.
Practise the same concept from this article. Your student profile may guide entitlement and follop recommendations, but it does not replace this concept.