Maths
Stretch – Circumference & Area of Circles
Stretch (independent-school 11+): calculate the circumference and area of a circle using π ≈ 3.14.
MathsAge 11+25 minutes
What this topic covers
- Use C = πd (or 2πr) with π ≈ 3.14 or π ≈ 3.
- Use A = πr² and distinguish it from circumference.
- Solve problems with semicircles and quarter circles.
Core concept summaries
Key ConceptsCircumference: π × DiameterArea: π × Radius²Semicircles and the Two Traps
Practice formats pupils may meet
NeurofiED uses varied practice to help pupils apply the idea actively, check understanding and build confidence over time.
clozematchingquiz
Example quiz question
Diameter 10 cm. Circumference (π ≈ 3.14)?
- 15.7 cm
- 314 cm
- 62.8 cm
- 31.4 cm
Show the answer
Answer: D. 31.4 cm
π × 10.