Sector area formula
Area = (1/2) * r^2 * theta (radians). The fraction of the circle is theta / (2*pi). Arc length = r * theta.
Sector Area Calculator
Calculate the area of a circular sector and its fraction of the full circle from radius and central angle.
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78.54
Sector area
25%
Fraction of circle
15.71
Arc length
314.16
Full circle area
90°
Angle in degrees
Also in Circles
Geometry
Sector area and fraction of circle
The sector area calculator finds the area of a circular sector from radius and central angle, showing what fraction of the full circle the sector represents.
Limitations
Angles should be between 0 and 360 degrees (0 to 2*pi radians).
Frequently asked questions
One quarter (25%). 90/360 = 0.25.
A sector is a "pie slice" (bounded by two radii and an arc). A segment is the region between a chord and its arc.
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