Pearson Edexcel International GCSE in Mathematics (Specification A) · 4MA1 · Free · no account needed
Geometry
Angle facts with named reasons, the special shapes, polygons, and bearings — where the reasons earn as many marks as the arithmetic.
Every lesson here ends the same way: learn it, teach it to an AI pupil who asks the awkward question, then defend it against the thinker with the strongest claim on it — free · no account needed.
4 modules of Pearson Edexcel International GCSE Mathematics, each explained in full — what it is, why it works, when a question is asking for it, the mistakes that cost marks and worked examples — with five graded questions marked on your own device. Completely free.
The modules in Geometry
Angles & Parallel Lines
Angle facts on lines, at points and between parallels — and the exam habit that doubles your marks: naming the reason for every step. The core facts: angles on a straight line sum to 180°; angles around a point sum to 360°; vertically opposite angles are equal.
When a question is asking for it: Any diagram with angles — and crucially, whenever the question says 'give reasons'. Learn Angles & Parallel Lines →
Triangles & Quadrilaterals
The special triangles and quadrilaterals, their angle totals, symmetries and diagonal properties — the shape vocabulary of every geometry question. Quadrilateral angles sum to 360°.
When a question is asking for it: Angle chases in quadrilaterals; 'how many lines of symmetry?'; and any question naming a special shape — the name is a licence to use every property in its bundle, and questions rely on you cashing it. Learn Triangles & Quadrilaterals →
Polygons
Interior and exterior angles of any polygon — driven by the one unbreakable fact that exterior angles always total 360°. For any polygon: the EXTERIOR angles sum to 360°, always.
When a question is asking for it: 'How many sides?' from an angle (go via the exterior angle — it divides 360), interior-angle sums, and tiling/meeting-point questions where angles at a point must total 360°. Learn Polygons →
Bearings & Scale Drawings
Three-figure bearings measured clockwise from north, back-bearings, and map scales — the navigation mathematics on both papers. A bearing is a direction given as a THREE-figure angle measured clockwise from north: due east is 090°, due south 180°, due west 270°.
When a question is asking for it: Any 'bearing of B from A' phrasing — the bearing is measured AT the point after 'from'. Learn Bearings & Scale Drawings →
The mistakes that cost marks in Geometry
One from each module — the error examiners see most, with the module that puts it right.
- Writing 'Z angles' in an answer. Examiners credit 'alternate angles' — the informal names score nothing. (Angles & Parallel Lines)
- Quadrilateral angles summing to 180°. Two triangles' worth: 360°. (Triangles & Quadrilaterals)
- Exterior angles summing to (n − 2) × 180. That's the INTERIOR sum; exteriors always make exactly 360°. (Polygons)
- Measuring at the wrong point: 'bearing of P from Q' is measured standing AT Q. (Bearings & Scale Drawings)
Where Geometry sits in the specification
Content area 4 of 4MA1, sub-topics 4.1, 4.7, 4.3, 4.2, 4.5. Incandio is aligned to the specification and is not published by Pearson; the numbers are given so you can check every module against your own copy.
- 4.1 — Bearings
- 4.7 — Geometrical reasoning
- 4.3 — Symmetry
- 4.2 — Polygons
- 4.5 — Scale drawings
How Geometry is mastered on Incandio
Every module above ends the same way: five questions that climb Grade 6 → 9+, then you teach the method back to Ember, an AI pupil who asks the awkward question, and defend it against the mathematician with the strongest claim on it. Exam Ready carries 37 authored exam-style questions across this strand, marked on Incandio.
All of Incandio Mathematics · The 4MA1 specification · Exam Ready