Area of sectors of a circle (Sectors are like "pizza" pie slices of a circle.)

Semi-circle
(half of circle = half of area)

Quarter-circle
(¼ of circle = ¼ of area)

Any Sector
(fractional part of the area)

n = degrees in central angle of sector

FYI
Topic
:

Regular polygons have all sides of equal length.

a = apothem p = perimeter

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