CDS Mathematics · Teaching notes
Lines, Angles and Polygons — CDS Elementary Mathematics
Lines, Angles and Polygons has 22 past-year questions in CDS Elementary Mathematics, in 11 of the twenty-one sittings from 2016 (II) to 2026 (II). None is HARD: 12 ask about angles made by lines and parallels, and 10 about the angles of polygons. The first page covers lines, angles and parallels; the second, polygon angle sums.
Every subtopic, worked example, formula and trap in one printable document — answers shown, ready to share.
Subtopic notes
Lines, Angles and Parallels
12 PYQsAngles on a straight line add to 180°, vertically opposite angles are equal, and a transversal makes equal corresponding and alternate angles with parallel lines.
Angles of Polygons
10 PYQsThe interior angles of an n-sided polygon add to (n − 2) × 180°, and its exterior angles always add to 360°.
Formula & revision sheet
3 formulas · 3 gotchas across all subtopics — the exam-eve cheat-sheet
Formula & revision sheet
3 formulas · 3 gotchas across all subtopics — the exam-eve cheat-sheet
Formulas (2)
Watch out for (2)
- Two bisectors, not one→ Angles where lines meet
- Equal angles, opposite slopes→ Parallels and transversals
Watch out for (1)
- Exterior angles sum to 360° always→ Interior and exterior angle sums
PYQ weightage by concept
3 concepts · 22 PYQs — where the marks actually sit, so you know what to drill first
PYQ weightage by concept
3 concepts · 22 PYQs — where the marks actually sit, so you know what to drill first
| Concept | PYQs | Share |
|---|---|---|
| Angles where lines meet | 6 | 27% |
| Parallels and transversals | 6 | 27% |
Test yourself on Lines, Angles and Polygons
10 past CDS questions from this chapter, timed at 12 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.