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# can anybody tell me how to calculate circumference of sector?

area of sector and circumference

### 5 Answers

- 1 decade agoFavorite Answer
area of sector=(180*square of radius)/angle of sector in radians

circumference=(360*radius)/angle of sector in radians

- 1 decade ago
The area of a circle is πr2 (2 means squared since we can't put it on superscript) and the circumference is 2πr.

Let's start with the area first. Since a sector is a portion of the circle,

Area of Sector= Angle of Sector/360 degrees x πr2

The circumference is more difficult.

Circumference= (Angle of Sector/360 degrees x 2πr) + 2r

This is because 2πr only calculates the outer part but not the radius itself.

To sum it up,

Area of Sector= Angle of Sector/360 degrees x πr2

Circumference= (Angle of Sector/360 degrees x 2πr) + 2r

Note: π here means 22/7 or 3.14, but it depends on what the question wants.

- 1 decade ago
Circumference of a sector = (x/360)*2*(22/7)*r

where x = angle of sector

r = radius of sector

- Anonymous5 years ago
Distance from O to S is length of radius = 2 cm Area of circle = πr² = 4π cm² A whole circle is 2π radians Sector is π/5 radians So area of sector is (π/5) / (2π) = 1/10 of area of circle Area of sector = 1/10 *4π cm² = 2π/5 cm²

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- Anonymous5 years ago
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You're close enough :P You said that R and S are on the circle, and O is in the centre. The distance from the centre of a circle to the edge is the radius! So the radius of the circle is: 2cm The formula for a section of a circle is: Area of Section = (Angle in degrees/360)*(pi)(r^2) or Area of Section = (Angle in radians/2)*(r^2) So the area is: (pi/10)*(4) = 2pi/5