Pie Charts
Grade 3The idea behind a pie chart
A pie chart shows how a total is split between categories. The whole circle is 360° and represents the whole data set. Each slice's angle is proportional to its share of the total.
The big trap: if the question asks you to draw a pie chart, you must work out angles first — never guess the size of a slice by eye.
The formula you need
Worked example — drawing a pie chart
Reading a pie chart — reverse the formula
Try this one
A pictogram shows the number of sandwiches sold at a cafe. The key states that each full symbol represents 8 sandwiches.
| Day | Symbols |
|---|---|
| Monday | 4 full symbols |
| Tuesday | 3 full symbols and 1 half symbol |
| Wednesday | 2 full symbols and 1 half symbol |
(a) Work out the total number of sandwiches sold across all three days. [3]
(b) The cafe owner says: "More than 80 sandwiches were sold in total over these three days." Is the owner correct? Show your working. [1]
Interpreting pictograms: convert each row to a number of sandwiches by multiplying full symbols by the key value and adding half the key value for each half symbol.
Ask yourself: 'What is half of 8, and have I accounted for every full and half symbol in each row before adding them all together?'
