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Lines of symmetry

PROCEDURAL
Mathematics›Geometry|Ages 8—9|ID: mt_hR2Y7NhMSY

Complete a simple symmetric figure with respect to a specific line of symmetry

Mastery Evidence

  • Given half a butterfly shape and a mirror line, complete the other half on a grid
  • Complete a symmetric pattern on squared paper with a vertical line of symmetry
  • Check a completed figure by folding along the mirror line

Assessment Prompt

“If you show [child] half a shape drawn on squared paper with a mirror line marked, can they draw the missing half so the whole shape is perfectly symmetrical?”

Prerequisites2

Show full prerequisite tree
  • 2-D shapes (age 8+) hard

    Must identify lines of symmetry before completing symmetric figures

    • 2-D shapes (age 6+) hard

      Vertical line symmetry in Y2 is prerequisite to finding symmetry lines in multiple orientations

      • 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

    • Transformations on a grid hard

      Identifying lines of symmetry requires the ability to draw and interpret reflection on a grid

  • Transformations on a grid hard

    Completing a symmetric figure requires performing a reflection on a grid accurately

Unlocks1