What Is an Angle?

CONCEPTUAL

Mathematics›Geometry|Ages 9—10|ID: mt_3S10OOGPqu

Understand that an angle is a geometric shape formed by two rays sharing a common endpoint (vertex); recognise angles in real-life contexts and 2-D shapes

Mastery Evidence

Identify the vertex and arms of an angle in a diagram
Find examples of angles in the classroom (e.g. open door, clock hands)
Explain why two rays meeting at a point form an angle

Assessment Prompt

“If you draw two lines starting from the same point on paper, can [child] tell you that the space between them is an angle — and point to the vertex where they meet?”

Prerequisites2

Types of angles
hardAges 8—9
Right Angles & Turns
hardAges 7—8

Show full prerequisite tree

Types of angles hard
Angle definition builds on understanding right angles
- Right Angles & Turns hard
  Identifying right angles and greater/less than right angle is prerequisite to naming acute/obtuse
  - Understanding angles hard
    Identifying right angles requires understanding what an angle is
    - 2-D shapes (age 6+) soft
      Understanding angles as shape properties requires knowing basic shape properties
      - Angles in triangles (age 6+) soft
        Understanding defining attributes supports describing shape properties formally
        
        2-D shapes hard
        Distinguishing defining vs non-defining attributes requires knowing common 2-D shape names first
        
        3-D shapes (age 5+) hard
        Identifying defining attributes builds on informal analysis and comparison of shapes
        
        2-D shapes hard
        Analysing and comparing shapes requires being able to name them first
        
        3-D shapes hard
        Analysing 3-D shapes requires recognising and naming them
      - 2-D shapes hard
        Describing properties of 2-D shapes (sides, symmetry) requires knowing the shapes first
      - 3-D shapes (age 5+) hard
        Formal property description extends informal analysis of sides and vertices
        
        2-D shapes hard
        Analysing and comparing shapes requires being able to name them first
        
        3-D shapes hard
        Analysing 3-D shapes requires recognising and naming them
    - Position, direction, and movement hard
      Recognising angles as turns extends Y2 work on quarter/half/three-quarter turns
      - Positional Language hard
        Position/direction vocabulary with right angles extends basic positional language
      - Turns & Directions hard
        Right-angle turns (clockwise/anti-clockwise) build directly on whole/half/quarter turns from Year 1
        
        What Is a Half? soft
        Understanding half and quarter turns benefits from the concept of halves and quarters
        
        Division as equal sharing hard
        Finding a half requires equal sharing into 2 groups — a division concept
        
        Subtraction as taking away or separating hard
        Division as equal sharing/grouping requires understanding subtraction as taking away/separating
        
        How Many in Total? hard
        Understanding subtraction as taking away requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
        
        Positional Language hard
        Describing movement and turns builds on positional language
  - Types of angles (age 8+) soft
    Identifying right angles and turns is supported by the convention of marking right angles with a small square
  - Position, direction, and movement hard
    Right angles as quarter turns extends Y2 turn vocabulary
    - Positional Language hard
      Position/direction vocabulary with right angles extends basic positional language
    - Turns & Directions hard
      Right-angle turns (clockwise/anti-clockwise) build directly on whole/half/quarter turns from Year 1
      - What Is a Half? soft
        Understanding half and quarter turns benefits from the concept of halves and quarters
        
        Division as equal sharing hard
        Finding a half requires equal sharing into 2 groups — a division concept
        
        Subtraction as taking away or separating hard
        Division as equal sharing/grouping requires understanding subtraction as taking away/separating
        
        How Many in Total? hard
        Understanding subtraction as taking away requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
      - Positional Language hard
        Describing movement and turns builds on positional language
Right Angles & Turns hard
Angle definition builds on classifying acute/obtuse angles
- Understanding angles hard
  Identifying right angles requires understanding what an angle is
  - 2-D shapes (age 6+) soft
    Understanding angles as shape properties requires knowing basic shape properties
    - Angles in triangles (age 6+) soft
      Understanding defining attributes supports describing shape properties formally
      - 2-D shapes hard
        Distinguishing defining vs non-defining attributes requires knowing common 2-D shape names first
      - 3-D shapes (age 5+) hard
        Identifying defining attributes builds on informal analysis and comparison of shapes
        
        2-D shapes hard
        Analysing and comparing shapes requires being able to name them first
        
        3-D shapes hard
        Analysing 3-D shapes requires recognising and naming them
    - 2-D shapes hard
      Describing properties of 2-D shapes (sides, symmetry) requires knowing the shapes first
    - 3-D shapes (age 5+) hard
      Formal property description extends informal analysis of sides and vertices
      - 2-D shapes hard
        Analysing and comparing shapes requires being able to name them first
      - 3-D shapes hard
        Analysing 3-D shapes requires recognising and naming them
  - Position, direction, and movement hard
    Recognising angles as turns extends Y2 work on quarter/half/three-quarter turns
    - Positional Language hard
      Position/direction vocabulary with right angles extends basic positional language
    - Turns & Directions hard
      Right-angle turns (clockwise/anti-clockwise) build directly on whole/half/quarter turns from Year 1
      - What Is a Half? soft
        Understanding half and quarter turns benefits from the concept of halves and quarters
        
        Division as equal sharing hard
        Finding a half requires equal sharing into 2 groups — a division concept
        
        Subtraction as taking away or separating hard
        Division as equal sharing/grouping requires understanding subtraction as taking away/separating
        
        How Many in Total? hard
        Understanding subtraction as taking away requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
      - Positional Language hard
        Describing movement and turns builds on positional language
- Types of angles (age 8+) soft
  Identifying right angles and turns is supported by the convention of marking right angles with a small square
- Position, direction, and movement hard
  Right angles as quarter turns extends Y2 turn vocabulary
  - Positional Language hard
    Position/direction vocabulary with right angles extends basic positional language
  - Turns & Directions hard
    Right-angle turns (clockwise/anti-clockwise) build directly on whole/half/quarter turns from Year 1
    - What Is a Half? soft
      Understanding half and quarter turns benefits from the concept of halves and quarters
      - Division as equal sharing hard
        Finding a half requires equal sharing into 2 groups — a division concept
        
        Subtraction as taking away or separating hard
        Division as equal sharing/grouping requires understanding subtraction as taking away/separating
        
        How Many in Total? hard
        Understanding subtraction as taking away requires knowing numbers represent quantities (cardinality)
        
        One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
    - Positional Language hard
      Describing movement and turns builds on positional language

Unlocks1

Degrees and turns
hardAges 9—10