Shape 3 summary

Key learning points

• Circumference $\pi d$ or $2\pi r$; area $\pi r^2$.
• Arc/sector use the fraction $\frac{\theta}{360}$.
• Segment = sector ± triangle.
• State decimal accuracy when using approximate $\pi$.

Worked example 1 — Sector

Radius 6, angle $90^\circ$. Sector area in terms of $\pi$?

Working

A quarter of $\pi r^2$.

Worked example 2 — Circumference or ; area

Use this method from the Shape 3 sheet: Circumference $\pi d$ or $2\pi r$; area $\pi r^2$.

Working

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

Worked example 3 — Arc/sector use the fraction

Use this method from the Shape 3 sheet: Arc/sector use the fraction $\frac{\theta}{360}$.

Working

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

Worked example 4 — Segment = sector ± triangle

Use this method from the Shape 3 sheet: Segment = sector ± triangle.

Working

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

Worked example 5 — State decimal accuracy when using approximate

Use this method from the Shape 3 sheet: State decimal accuracy when using approximate $\pi$.

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.