MA25-04 Maths Coming soon
Chaining angle facts together with reasons
MA25-04
This lesson is coming soon.
In this lesson
Combine two or more angle facts in sequence within one diagram, writing a reason at each step that genuinely matches the method used at that step.
What it covers
- Working through two or three linked angle-fact steps within a single rectilinear diagram (combining point/line/vertically-opposite/parallel/triangle facts)
- Writing a reason at each individual step that matches exactly what was calculated at that step, not one blended reason for the whole answer
- Recognising which angle fact applies next once the previous step's angle has been found
Key words
For: OCR GCSE J560
On the specification
| Board | Spec | Statement |
|---|---|---|
| OCR GCSE J560 | 8.03a | Know and use the sum of the angles at a point is 360°. |
| OCR GCSE J560 | 8.03b | Know that the sum of the angles at a point on a line is 180°. |
| OCR GCSE J560 | 8.03c | Know and use: vertically opposite angles are equal; alternate angles on parallel lines are equal; corresponding angles on parallel lines are equal. |
| OCR GCSE J560 | 8.03d | Derive and use the sum of the interior angles of a triangle is 180°. Derive and use the sum of the exterior angles of a polygon is 360°. Find the sum of the interior angles of a polygon. Find the interior angle of a regular polygon. |
For teachers
This GCSE Maths lesson teaches chaining angle facts together with reasons. By the end, students should be able to combine two or more angle facts in sequence within one diagram, writing a reason at each step that genuinely matches the method used at that step. It works through two worked examples and the mistakes examiners report.