Foundation and Higher · pie charts
Pie charts.
360° shared out.
degrees per person
is the key
a full turn shared between everyone —
360°
find the angle for one person
then multiply
step 1 of 4
Degrees per person
1. Add the frequencies: 40 students.
2. Share 360° between them.
✓ Each student is worth 9°
40 students: walk 18, bus 12, car 10
360 ÷ 40
= 9° per student
step 2 of 4
Work out the angles
1. Multiply each frequency by 9.
2. Check that the angles add up to 360°.
✓ If they do not, recheck
walk: 18 × 9 = 162°
bus: 12 × 9 = 108°
car: 10 × 9 = 90°
162 + 108 + 90 = 360 ✓
step 3 of 4
Draw it
1. Start with a line straight up.
2. Measure each angle from the last line.
✓ Label every sector
step 4 of 4
Read one backwards
1. Find the degrees per person again.
2. Then see how many fit into 360°.
✓ Same idea, other direction
a 72° sector stands for 8 people
72 ÷ 8 = 9° per person
360 ÷ 9
= 40 people in total
pie charts —
Per person
360 ÷ total frequency
Each angle
frequency × degrees per person
Check
the angles add to 360°
Two pie charts? Bigger sector does not
mean more people. Check the totals.
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