#25 · Circles · Classes 7–12
Quadrant
A quarter of a circle: a sector with a 90° angle.
Quadrant📐 Formula
Area = ¼πr²; Perimeter = ½πr + 2r
✏️ Worked example
r = 4: area = 4π ≈ 12.57, perimeter ≈ 14.28.
🌍 Where it is used
Corner shelves and the sweep of a door.
❓ Quick check
A quadrant’s angle is…