This introduction covers The Most Famous Number in Maths within Circumference & Area of Circles for GCSE Mathematics. Revise Circumference & Area of Circles in Geometry & Measures for GCSE Mathematics with 11 exam-style questions and 7 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 1 of 10 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
The Most Famous Number in Maths
For thousands of years, mathematicians noticed something magical: if you divide ANY circle's circumference by its diameter, you ALWAYS get the same number - π (pi) = 3.14159... This single number unlocks both the distance around a circle AND the space inside it!
Practice questions for Circumference & Area of Circles
A circle has radius r. Which pair of formulas gives the correct circumference C and area A?
Explain why the circumference of a circle is measured in cm (or other length units) but the area is measured in cm² (square units).
Quick recall flashcards
Circumference
C = πd or C = 2πr
Area of Circle
A = πr²