A pie chart divides a whole into sectors. Values are given either in percentages (summing to 100) or in degrees (summing to 360°).
1Conversions
Central angle = percentage × 3.6°
Percentage = central angle ÷ 3.6
Amount for a sector = percentage × total ÷ 100
2Comparisons
Ratios between sectors are ratios of their percentages; the total is not needed
'A is x% more than B' ⇒ x = (A − B)/B × 100