MA27-06 Maths Coming soon
Circle theorem: tangent and radius
MA27-06
This lesson is coming soon.
In this lesson
Prove and use the circle theorem that a tangent is perpendicular to the radius (or diameter) at the point of contact, treating the word 'tangent' as an immediate trigger for a 90-degree angle.
What it covers
- A tangent to a circle is perpendicular to the radius (or diameter) at the point of contact
- Recognising the word 'tangent' in a question, even without a fully-drawn radius, as an immediate trigger for a 90-degree angle
Key words
For: OCR GCSE J560, Edexcel IGCSE 4MA1, AQA GCSE 8300, Edexcel GCSE 1MA1, Eduqas GCSE C300, Cambridge IGCSE 0580
On the specification
| Board | Spec | Statement |
|---|---|---|
| OCR GCSE J560 | 8.05f | Apply and prove: for a point P on the circumference, the radius or diameter through P is perpendicular to the tangent at P. |
| Edexcel IGCSE 4MA1 | F4.6B | Understand chord and tangent properties of circles |
| AQA GCSE 8300 | G10 | Apply and prove the standard circle theorems concerning angles, radii, tangents and chords, and use them to prove related results |
| Edexcel GCSE 1MA1 | G10 | Apply and prove the standard circle theorems concerning angles, radii, tangents and chords, and use them to prove related results |
| Eduqas GCSE C300 | HG10 | Apply and prove the standard circle theorems concerning angles, radii, tangents and chords, and use them to prove related results |
| Cambridge IGCSE 0580 | C4.7 | Circle theorems |
| Cambridge IGCSE 0580 | E4.7 | Circle theorems I |
For teachers
This GCSE Maths lesson teaches circle theorem: tangent and radius. By the end, students should be able to prove and use the circle theorem that a tangent is perpendicular to the radius (or diameter) at the point of contact, treating the word 'tangent' as an immediate trigger for a 90-degree angle. It works through two worked examples and the mistakes examiners report.