Interpreting pie charts | Maths | Quizalize & Oak National Academy

Starter quiz

120 people were asked: "what do you most frequently drink whilst at work". The results will be placed in a pie chart with a total of 20 pre-defined sectors. How many sectors would represent water?
- 3.6
- 6
- 12 ✓
- 72
- 360
120 people were asked: "what do you most frequently drink whilst at work". The results will be placed in a pie chart with a total of 20 pre-defined sectors. How many people voted for milk?
- '24' ✓
A large set of information is collected and represented in a pie chart of 30 equally-sized sectors. Each sector represents a frequency of 40. What is the total frequency of this dataset?
- '1200' ✓
Which of these words is not an essential feature of a pie chart or the calculations required to construct a pie chart?
- radius
- sector
- linear ✓
- frequency / value
- pi ( $\pi$ ) ✓
The incomplete ratio table shows a dataset being converted into angles to represent each subgroup as sectors on a pie chart. Match the letters to the correct missing values.
- a
  
  ⇔
  
  120 ✓
- b
  
  ⇔
  
  360 ✓
- c
  
  ⇔
  
  3 ✓
- d
  
  ⇔
  
  54 ✓
- e
  
  ⇔
  
  132 ✓
The incomplete ratio table shows a dataset being converted into angles to represent each subgroup as sectors on a pie chart. Find the value of angle a, in degrees.
- '160' ✓

The table shows the number of people at Location 1 and their preferred cooking style for potatoes. By choosing an appropriate row to perform calculations on, find the value of the unknown multiplier.
- 40
- 9
- 3 ✓
- 13
- 39
The table shows the number of people at Location 2 and their preferred cooking style for potatoes. Find the multiplier linking frequency and angle.
- '2' ✓
Find the number of people who preferred boiled potatoes.
- '36' ✓
Match the missing number (labelled by a letter) in the ratio table with its correct value.
- a
  
  ⇔
  
  4 ✓
- b
  
  ⇔
  
  128 ✓
- c
  
  ⇔
  
  72 ✓
- d
  
  ⇔
  
  18 ✓
- e
  
  ⇔
  
  90 ✓
Below are correctly drawn pie charts showing the preferred cooking methods for potatoes for people at Locations 4 and 5. Select the statements that are always true.
- The same number of people (25 people) voted for boiled at both Locations 4 and 5
- The same percentage of people (25%) voted for boiled at both Locations 4 and 5 ✓
- A greater number of people voted for roasted in Location 5 than Location 4
- A greater proportion of people voted for roasted in Location 5 than Location 4 ✓
- The same number of people voted in Locations 4 and 5
75 people voted for roasted in Location 4. By using a protractor and this information, calculate the total frequency of the people who voted in Location 4.
- '200' ✓

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Knowing the angle size for a sector allows calculation of the frequency.
By knowing the total, statements can be made comparing the data.
Different pie charts may have different totals even though proportions are the same.

Two sectors on two different pie charts that have the same angle represent the same frequency.

90° of a pie chart of 4 data points represents less frequency (frequency of 1) than 90° of a pie chart of 200 data points (frequency of 50).

Pie chart - A pie chart (pie graph) is a circular graph where sectors represent different groups proportionally.
Frequency - The frequency is the number of times an event occurs; or the number of individuals (people, animals etc.) with some specific property.
Sector - A sector is the region formed between two radii and their connecting arc.
Proportion - Proportion is a part to whole (sometimes part to part) comparison. If two things are proportional, the ratio of part to whole is maintained
Degrees - Degrees are the most common unit of measurement for angle. One whole turn is equal to 360 degrees, written 360°.