Types of angles
Identify acute and obtuse angles; compare and order angles up to two right angles by size
Lesson
Set out your lesson
“Types of 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 Types of angles, add one harder example after success.
What to notice. Keep one parent note: examples tried; results; support used. This session samples Types of angles, not mastery.
Share and support
Family records and proof options
Keep a record of your learning
Save photos, notes, and attendance. Export a proof packet for compliance or portfolio reviews.
Practice this concept
Start practiceTypes of angles practice
Practice key ideas from Types of 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.
Illustrative Mathematics · Practice link — not the full lesson
Finding an unknown angle
Before you open · source notes
Finding an unknown angle supports classifying and reasoning about angle types. Not every protractor construction lesson.
Free, no sign-in. A teacher solution is on the same page, so use the student view with your child.
Before you openAsk the learner to find the unknown angle and name whether it is acute, right, or obtuse.
Opening this link does not save learning or assess mastery.
Source, access and review notes
Public Illustrative Mathematics task page. The .html address responds HTTP 308 to this URL. An anonymous GET of this URL on 2026-11-12 returned HTTP 200 with no login or payment prompt. Where a teacher solution is present, it is on the same page as the student task; this check did not find a separate locked student view. An adult can use the student view section and should not read a solution aloud. Advertising was not observed in the fetched HTML text; that is not a browser, device, or ad-free guarantee. This is a paper or discussion task, not an automatically marked interactive game. Opening the link does not save practice or assess mastery. Diagrams on the page use missing or filename-only alt text, so they are not an accessible image equivalent. Accessibility still depends on an adult describing the picture.
Illustrative Mathematics. “Finding an unknown angle.” Licensed CC BY-NC-SA 4.0. External task; Gakuva does not copy, host, embed, or redistribute it.
CC BY-NC-SA 4.0 — link only
Check understanding
- Classify given angles as acute, right, or obtuse
- Order four angles from smallest to largest by visual comparison
- Identify all acute and obtuse angles in a given triangle or quadrilateral
“If your child looks at the hands on a clock showing different times, can they tell you which angle between the hands is acute (sharper than a right angle) and which is obtuse (wider)?”
Curriculum record
- Type
- Conceptual
- Subject
- Mathematics
- Domain
- Geometry
- Age range
- Ages 8–11
Standards