Learning pack · Foundation · CIE Core

Polygons

What's in this pack: printable worksheet PDF, matching answers PDF, and slides (Foundation · CIE Core depth). Polygon angle sums and regular-polygon exterior angles are standard: exterior angles of any convex polygon sum to $360^\circ$ .

Resources at the top · full summary · videos with short notes below.

🎒 Resources in this pack

Jump straight to the printable files, or scroll to the summary and videos.

Scaffolded Learning Sheet — attempt the worksheet, then use the Answers for a full written solution.

📝 Open Learning Sheet ✅ Open answers 🎬 More topic videos (6)📖 Full summary

Lesson slides · narrated video available

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Files: foundation-25 Polygons handout.pdf · foundation-25 Polygons handout answers.pdf

Full topic summary

Polygon angle sums and regular-polygon exterior angles are standard: exterior angles of any convex polygon sum to $360^\circ$ .

Key learning points

Interior sum of an $n$ -gon: $(n-2)\times180^\circ$ .
Regular polygon: each exterior $=360^\circ/n$ ; interior $=180^\circ-$ exterior.
Tessellation links to angles at a point.

Worked example 1 — Interior sum

Sum of interior angles of a hexagon?

Working

(6-2)\times180=720^\circ

$(n-2)\times180^\circ$ .

Worked example 2 — Regular hexagon

Each interior angle of a regular hexagon?

Working

\text{exterior}=60;\ \text{interior}=120

Exteriors sum to $360^\circ$ .

Worked example 3 — Exterior angle

Regular polygon, exterior $24^\circ$ . Number of sides?

Working

n=360/24=15

$n=360^\circ/\text{exterior}$ .

🎬 Topic videos

Pascal's Triangle - Numberphile
Numberphile · 13 min
Enrichment / curiosity clip for Lower Secondary (Numberphile-style). Use for hooks, clubs, or stretch — not core exam content.
All Triangles are Equilateral - Numberphile
Numberphile · 5 min
Enrichment / curiosity clip for Lower Secondary (Numberphile-style). Use for hooks, clubs, or stretch — not core exam content.
Triangles have a Magic Highway - Numberphile
Numberphile · 10 min
Enrichment / curiosity clip for Lower Secondary (Numberphile-style). Use for hooks, clubs, or stretch — not core exam content.
Too Many Triangles - Numberphile
Numberphile · 8 min
Enrichment / curiosity clip for Lower Secondary (Numberphile-style). Use for hooks, clubs, or stretch — not core exam content.
Squaring the Triangle - Numberphile
Numberphile · 14 min
Enrichment / curiosity clip for Lower Secondary (Numberphile-style). Use for hooks, clubs, or stretch — not core exam content.
3 Ways to Draw Squares Inside Triangles - Numberphile
Numberphile · 9 min
Enrichment / curiosity clip for Lower Secondary (Numberphile-style). Use for hooks, clubs, or stretch — not core exam content.

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