Circle theorems

Circle theorems for A Level Art and Design Edexcel Higher: what it means, how to set the working out, and the questions it is asked in.
  • A Level
  • Edexcel
  • Art and Design
  • Higher
  • Spec P8 · P2
  • 7 min read
  • 6 revision boxes

Introduction

2 boxes
2 min read

What is circle theorems?

Listen to this box

Transcript

A short spoken summary of circle theorems and where it is used.

A spoken walk-through of circle theorems before you read the notes.
Sketch the shape even when the question does not ask for one — it makes the next step obvious.
The layout below is the one the mark scheme expects.

Diagram showing circle theorems laid out step by step

The same idea drawn out, so the method is visible.
6 rows

The circle theorems reference table

Practise the routine version until it is automatic, then move to the multi-step questions.
The layout below is the one the mark scheme expects.

Diagram showing circle theorems laid out step by step

The same idea drawn out, so the method is visible.
Worth knowing: a2+b2=c2a^2 + b^2 = c^2.
Term
Meaning
Example
Common slip
Row 1 column 1
Row 1 column 2
a2+b2=c2a^2 + b^2 = c^2
Row 1 column 4
Row 2 column 1
Row 2 column 2
34×25\frac{3}{4} \times \frac{2}{5}
Row 2 column 4

Learning

2 boxes
4 steps

How to work with circle theorems

The examiner marks the working, so a correct answer with no method still drops marks.
The layout below is the one the mark scheme expects.

Diagram showing circle theorems laid out step by step

The same idea drawn out, so the method is visible.
Worth knowing: 49=7\sqrt{49} = 7.
  1. Read the question and write down what is being asked for.
  2. Set out the working for circle theorems in the order the method gives.
  3. Substitute the values and simplify.
Start from the definition and substitute the numbers the question gives you.
Simplify one line at a time: x2+5x+6=0x^2 + 5x + 6 = 0.
Answer: a2+b2=c2a^2 + b^2 = c^2
2 rules

Key facts: Circle theorems

This idea appears again in the higher-mark questions, so it is worth over-learning.
Worth knowing: 34×25\frac{3}{4} \times \frac{2}{5}.
  • Rule 1

    How circle theorems behaves in the 1st of the cases the specification names.
    160\approx 160
  • Rule 2

    How circle theorems behaves in the 2nd of the cases the specification names.
    49=7\sqrt{49} = 7
  • Rule 3

    How circle theorems behaves in the 3rd of the cases the specification names.
    a2+b2=c2a^2 + b^2 = c^2

20 minutes

Get your predicted grade

Twenty questions gives you a predicted grade, your target, and the gap between them — plus the topics that close it fastest.

Examples

2 boxes
4 marks · worked

Worked example: circle theorems

The specification wording is precise here, and the mark scheme follows that wording exactly.
Worth knowing: a2+b2=c2a^2 + b^2 = c^2.
4 marks · worked

Practice question 6: 34×25\frac{3}{4} \times \frac{2}{5}

This idea appears again in the higher-mark questions, so it is worth over-learning.

Practice bank

Thousands of revision questions

Every topic is backed by graded practice with instant marking and full solutions.
Try it now
Practice questions
5,000+
Topics
10
Marking and solutions
Instant

Common questions

How many marks is circle theorems usually worth?
Between one and four, depending on how many steps the question asks for.
Is this on the A Level Art and Design Edexcel Higher paper?
Yes — it sits in the Sources and evidence strand.