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MathematicsGeometryAges 9–12

Straight, reflex and revolution angles

Name, estimate and compare straight angles, reflex angles and revolutions alongside acute, right and obtuse angles, describing each by its relationship to a right angle (without measuring in degrees)

Lesson

Set out your lesson

“Straight, reflex and revolution angles means practising the idea at the table with counters or paper models and one clear check. We will demo once, then your child tries.”

Bring to the table

  • Paper shapes or a ruler and pencil
  • Shape name cards
Extra for the adult

Worked example. A rectangle has four right angles. Naming the property is the check.

Optional challenge. For Straight, reflex and revolution angles, add one harder example after success.

What to notice. Keep one parent note: examples tried; results; support used. This session samples Straight, reflex and revolution angles, not mastery.

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Family records and proof options

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Save photos, notes, and attendance. Export a proof packet for compliance or portfolio reviews.

Practice this concept

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Gakuva activity

Straight, reflex and revolution angles practice

Practice key ideas from Straight, reflex and revolution angles.

Free · no login · no ads · Practice answers and completion are not saved. Parent observation remains the lesson record.

Learning resources

Extra practice links — they do not replace Gakuva’s teaching approach.

BBC Bitesize · Practice link — not the full lesson

KS3 Maths

Open practice (new tab)
Before you open · source notes

KS3 Maths supports Straight, reflex and revolution angles. An adult previews and guides; this is a learning page, not a scored quiz.

Free educational page, no sign-in required for the tested path.

Before you open

Ask the learner one fact they learned and one question they still have.

Opening this link does not save learning or assess mastery.

Source, access and review notes

Public BBC Bitesize page. An anonymous GET on 2026-11-12 returned HTTP 200 with no login or payment prompt for this URL. Opening the link does not save practice or assess mastery. An adult should preview and guide the learner.

BBC Bitesize. “KS3 Maths.” External page; Gakuva does not copy, host, embed, or redistribute materials.

Unknown — link only

Check understanding

  • Identify a straight angle as two right angles and a revolution as four right angles
  • Sort angles from a set of drawn shapes into acute, right, obtuse, straight and reflex
  • Estimate whether an angle drawn between clock hands is less than or more than a straight angle
“If your child looks at the hands on a clock, can they say whether the angle between them is a straight line, smaller than a right angle, or bigger than a straight line (a reflex angle)?”

Curriculum record

Type
Conceptual
Subject
Mathematics
Domain
Geometry
Age range
Ages 9–12

Standards

acara-v9:AC9M4M04the-ontario-curriculum-mathematics-2020:ON-MATH-2020-G4-E2.4the-ontario-curriculum-mathematics-2020:ON-MATH-2020-G6-E2.2