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A sector is a slice of a circle made from two radii and the arc between them. The diagram shows the central angle θ\thetaθ and the curved edge, which is the arc length LLL.
A full circle is 360∘360^{\circ}360∘, so a sector with angle θ\thetaθ is the fraction θ360\frac{\theta}{360}360θ of the whole circle. This same fraction tells you how much of the full area and full circumference you are using.
Question 1
2 marksThe diagram shows a sector, centre OOO. The radius of the circle is 8 cm. The angle of the sector is 150∘150^\circ150∘.
For a circle with radius rrr, what is the area formula?
Revision notes for Edexcel GCSE Maths Sector Areas and Arc Lengths. Open the guide for explanations and worked examples. Written against the Edexcel GCSE Maths (1MA1) specification, so the content matches what's examinable rather than general Maths background.
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A sector has a central angle of 90°90°90°. What fraction of a full circle is the sector?
