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Diameter: GCSE Maths Definition

Naomi C

Written by: Naomi C

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1 minutes

Contents

  1. 1. What is a diameter?
  2. 2. Diameter Revision Resources to Ace Your Exams

What is a diameter?

In GCSE Maths, a diameter is a line that goes through the centre of a circle and whose ends touch the circumference at two different points. A diameter is a line of symmetry of a circle, as it cuts a circle exactly into two halves. 

A circle with a straight line crossing through the centre from one point on the circumference to another point on the circumference. The line is labelled “diameter”.
A circle showing a diameter

It is useful to remember that a diameter is twice the length of a radius for a circle. The diameter can be used to calculate the area or circumference of a circle, as well as having other applications in areas such as circle theorems.

Diameter Revision Resources to Ace Your Exams

Diameter is covered in our revision notes on 2D & 3D Shapes from GCSE Maths. You can also have a go at our related exam questions and flashcards to test your understanding. Don’t forget to check out the past papers for more general exam revision.

Explore Our GCSE Maths Revision Resources

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Naomi C

Author: Naomi C

Expertise: Maths

Naomi graduated from Durham University in 2007 with a Masters degree in Civil Engineering. She has taught Mathematics in the UK, Malaysia and Switzerland covering GCSE, IGCSE, A-Level and IB. She particularly enjoys applying Mathematics to real life and endeavours to bring creativity to the content she creates.

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