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Introduction:
Concepts of perimeter (circumference) and area of a circle and apply this knowledge in finding the areas of two special ‘parts’ of a circular region (or briefly of a circle) known as sector and segment To find the areas of some combinations of plane figures involving circles or their parts.
1.Circumference of a circle = 2 π r.
2. Area of a circle = π r2
3. Length of an arc of a sector of a circle with radius r and angle with degree θ is θ/(360°) × 2 π r
4. Area of a sector of a circle with radius r and angle with degrees measure θ is θ/(360°) × π r2
5. Area of segment of a circle = Area of the corresponding sector – Area of the corresponding triangle.