GCSE Maths revision · Probability and statistics

Charts and graphs

Foundation and Higher

The idea

Each chart shows data a different way. In a pie chart, angle $= \frac{\text{frequency}}{\text{total}} \times 360^\circ$ . In a frequency polygon, plot each frequency at the middle of its class.

Read the scale on each axis first.
For a pie chart, find the degrees for one item: $360^\circ \div$ total.
For a frequency polygon, plot at the class midpoints and join with straight lines.

Watch out Check that the pie chart angles add to $360^\circ$ .

See it worked

Worked exampleNon-calculator2 marks

A club asks 60 members to choose one activity. Fifteen choose climbing. The club plans to display the results in a pie chart. Work out the angle of the sector for climbing.

$15/60\times 360$
A full pie chart represents $360^\circ.$
Climbing accounts for 15/60 = 1/4 of the members.
The sector angle is 360 $\div$ 4 = $90^\circ.$

Answer $90$ °

Your turn

Question 1Non-calculator1 mark

A gardener measures the water level in a tank at noon on each of ten consecutive days. Which diagram is most suitable for showing how the water level changes over these days?

Question 2Non-calculator4 marks

A pie chart shows how some students travel to school. The sector for bus has an angle of $72^\circ$ and represents 18 students. The sector for car has an angle of $100^\circ$ .

(a) Work out how many students travel by car.

(b) Work out the total number of students in the survey.

Question 3Non-calculator3 marks

Two pie charts show the favourite sports of two classes. Class $A$ has 30 students; its football sector is $120^\circ$ . Class $B$ has 45 students; its football sector is $96^\circ$ . Jo says, "More students chose football in class $A$ , because its sector is bigger."

Is Jo correct? You must show how you get your answer.

In past papers

207 official questions in 145 papers since 2017. The latest:

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