S3StatisticsFoundation

Charts & Graphs

Charts turn data into a picture so patterns jump out. You need to read and draw bar charts, pictograms and pie charts — and know which chart suits which kind of data.

35 min AQA GCSE Maths

What you'll learn

Read and draw bar charts
Use pictograms with a key
Draw and interpret pie charts
Choose a suitable chart

Bar charts and pictograms

A $bar chart$ uses bars whose height shows the frequency — leave gaps between bars for separate categories. A $pictogram$ uses symbols, so always check the key to see how many each symbol represents.

Pie charts

A pie chart shows proportions as slices of a circle. Since a full circle is $360°$ , each item’s angle is its frequency divided by the total, times $360°$ .

angle = \frac{frequency}{total} \times 360°

Pie chart slice angle.

\frac{8}{40} \times 360°

= 72°

Answer

72°

Tip — Check your pie chart angles add up to 360°.

Remember these

pie angle = \frac{f}{total} \times 360°

Angle for each slice.

\sum angles = 360°

Pie chart check.

Watch out for these

Ignoring the key on a pictogram.

One symbol can represent more than one item — read the key.

Pie chart angles that do not add to 360°.

Total all angles to check they make 360°.

Key takeaways

Bar charts: bar height = frequency, gaps between categories.
Pictograms: always read the key.
Pie angle = (frequency ÷ total) × 360°.

Test yourself

Ready to practise Charts & Graphs? Pick a mode and earn XP & Dobloons.