This key facts covers Key Vocabulary 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 2 of 10 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Key Vocabulary
| Term | Meaning | Symbol |
|---|---|---|
| Radius | Distance from centre to edge | r |
| Diameter | Distance across through centre | d = 2r |
| Circumference | Perimeter (distance around) | C |
| Pi (π) | ≈ 3.14159... or use π button | π |
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
Area of Circle
A = πr²
Circumference
C = πd or C = 2πr