Shape 1 summary

Key learning points

• Straight line $180^\circ$; around a point $360^\circ$; triangle $180^\circ$.
• Use parallel-line angle rules with reasons.
• Mark equal angles on diagrams.
• State a reason for every angle chase step.

Worked example 1 — Straight line

Angles on a line: $65^\circ$ and $x$. Find $x$.

Working

$180-65$.

Worked example 2 — Straight line ; around a point ; triangle

Use this method from the Shape 1 sheet: Straight line $180^\circ$; around a point $360^\circ$; triangle $180^\circ$.

Working

Each key learning point matches a question type on the printable worksheet.

Worked example 3 — Use parallel-line angle rules with reasons

Use this method from the Shape 1 sheet: Use parallel-line angle rules with reasons.

Working

Each key learning point matches a question type on the printable worksheet.

Worked example 4 — Mark equal angles on diagrams

Use this method from the Shape 1 sheet: Mark equal angles on diagrams.

Working

Each key learning point matches a question type on the printable worksheet.

Worked example 5 — State a reason for every angle chase step

Use this method from the Shape 1 sheet: State a reason for every angle chase step.

Working

Each key learning point matches a question type on the printable worksheet.

Scaffolded Learning Sheet and answers (PDFs)

This page is a short, searchable overview for revision and search engines. Use the Scaffolded Learning Sheet first, then the Answers PDF for a full written solution. The printable PDFs remain the main classroom resource.