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Geometrical properties: polygons

Geometrical properties: polygons

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Why this why now

This unit builds on knowledge developed investigating angles and continues work done in the previous unit investigating polygons. Here pupils will develop understanding of external and internal angles of polygons and traversals through parallel lines

Prior knowledge requirements

  • Identify and classify polygons by sides and angles
  • Use angle rules (interior, exterior)
  • Calculate sum of angles and solve problems using reasoning

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Why this why now

This unit builds on knowledge developed investigating angles and continues work done in the previous unit investigating polygons. Here pupils will develop understanding of external and internal angles of polygons and traversals through parallel lines

Prior knowledge requirements

  • Identify and classify polygons by sides and angles
  • Use angle rules (interior, exterior)
  • Calculate sum of angles and solve problems using reasoning

Geometrical properties: polygons

In this unit pupils will investigate internal and external angles of polygons and angles made with a transveral and parallel lines. Pupils will develop their ability to formally prove properties of polygons to generalise.

16 lessons in unit

  1. 1

    Checking understanding of angles from KS2

    I can calculate with angles at a point, angles on a line and vertically opposite angles.
  2. 2

    Securing understanding of angles from KS2

    I can confidently state the sums of the angles around a point and on a straight line.
  3. 3

    Formalising understanding of triangles from KS2

    I can classify triangles and know their relevant properties.
  4. 4

    Formal angle notation

    I can use conventional terms and notations for lines, rays, segments and angles.
  5. 5

    Corresponding angles

    I can recognise that a pair of parallel lines traversed by a straight line produces equal corresponding angles.
  6. 6

    Alternate angles

    I can recognise that a pair of parallel lines traversed by a straight line produces equal alternate angles.
  7. 7

    Co-interior angles

    I can recognise that a pair of parallel lines traversed by a straight line produces supplementary co-interior angles.
  8. 8

    Angles on parallel lines traversed by a straight line

    I can use facts about a pair of parallel lines traversed by a straight line.
  9. 9

    The sum of the interior angles of any triangle

    I can demonstrate and prove that in a triangle, the sum of the interior angles is 180°.
  10. 10

    Using the sum of the interior angles of a triangle

    I can use the fact that the interior angles of any triangle sum to 180° to find the size of missing angles.
  11. 11

    Interior angles of a polygon

    I can find the interior angle of any polygon.
  12. 12

    Deriving the sum of interior angles in multiple ways

    I can use reasoning to derive the sum of interior angles in multiple ways.
  13. 13

    Exterior angles of polygons

    I can find the sum of the exterior angles of a polygon.
  14. 14

    Interior and exterior angles of regular polygons

    I can find the interior and exterior angles of regular polygons.
  15. 15

    Missing angles

    I can solve problems that require a combination of angles facts to identify values of missing angles, providing explanations of reasoning and logic used.
  16. 16

    Problem solving with polygons

    I can use my knowledge of polygons to solve problems.

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