# How do you find the central angle of a pie chart for a section of the pie chart that represents 20% of the pie?

Feb 25, 2018

20% " of " 360° = 72°

#### Explanation:

In any sector, there are $3$ parts to be considered:

the arc length,
the sector area
the sector angle

They all represent the SAME fraction of the whole circle.

The arc length is a fraction of the circumference
The sector area is a fraction of the whole area
The sector angle is a fraction of 360°

If the sector is 20% of the pie chart, then each of these parts is 20% of the whole.

The sector angle is therefore:

20% xx 360°

20/100 xx 360 =72°