Class 10 Maths Chapter 11 Areas Related to Circles Revision Notes

Class 10 Maths Chapter 11 – Areas Related to Circles: Quick Revision Notes

Circumference of a circle = 2πr
Area of a circle = πr²
Length of an arc = (θ/360) × 2πr
Area of a sector = (θ/360) × πr²
Area of a sector (using arc length l) = (1/2) × l × r
Area of a segment = Area of sector − Area of triangle = (θ/360)πr² − (1/2)r²sinθ
Minor segment + Major segment = Area of circle
Minor sector + Major sector = Area of circle
Quadrant (θ=90°): Area = (1/4)πr²
Semicircle (θ=180°): Area = (1/2)πr²
Area of a ring/annulus (radii R > r) = π(R² − r²)
Angle swept by minute hand = 6° per minute; by hour hand = 0.5° per minute
Use π = 22/7 or 3.14 strictly as specified in the question