7
CBSE Marks
★★★★★
Difficulty
9
Topics
Medium
Board Weight
Topics Covered
9 key topics in this chapter
Perimeter & Area of Circle
Length of an Arc
Area of Sector
Area of Minor & Major Sector
Area of Segment
Area of Minor & Major Segment
Areas of Combination of Plane Figures
Shaded Region Problems
Flower & Petal Patterns
Study Resources
Key Formulas
| Formula / Rule | Expression |
|---|---|
| Circumference | \(2πr\) |
| Area of Circle | \(πr²\) |
| Arc Length | \((θ/360°)·2πr\) |
| Area of Sector | \((θ/360°)·πr²\) |
| Area of Triangle (sector) | \(½·r²·sin θ\) |
| Area of Segment | \(Area of Sector − Area of Triangle\) |
Important Points to Remember
The area of a sector depends on both the radius and the central angle.
Area of minor segment = Area of sector − Area of triangle.
For combined figures: sketch carefully, identify each sub-region, apply the correct formula.
Use π = 22/7 unless the problem specifies otherwise.