CIR004 · Circles · Classes 4–12
Circle
All points at the same distance r (radius) from the centre. Diameter d = 2r.
Circle📐 Formula
Area = πr²; Circumference = 2πr
✏️ Worked example
r = 7: area = 49π ≈ 153.94 (154 with π = 22/7), circumference ≈ 43.98 (44).
🌍 Where it is used
Wheels, coins, clocks and plates.
❓ Quick check
Circumference of a circle of radius 14 (π = 22/7):