Class 10 · Mathematics (Basic) · Unit 11: Areas Related to Circles

Sector of a Circle

Lesson 2 of 6

The region bounded by two radii and the arc between them is a sector. If the angle at the centre is

\theta

(in degrees), arc length

= \dfrac{\theta}{360}\cdot 2\pi r

; sector area

= \dfrac{\theta}{360}\cdot \pi r^2

. Alternatively, in radians: arc

= r\theta

, area

= \tfrac{1}{2}r^2\theta

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