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Cotmanhay Junior School

Safe, Happy Learning

Week 3 - 5 Properties of shape

National curriculum content


  • Draw 2-D shapes using given dimensions and angles
  • Recognise, describe and build simple 3-D shapes, including making nets
  • Compare and classify geometric shapes based on their properties and sizes and find unknown angles in any triangles, quadrilaterals, and regular polygons
  • Illustrate and name parts of circles, including radius, diameter and circumference and know that the diameter is twice the radius
  • Recognise angles where they meet at a point, are on a straight line, or are vertically opposite, and find missing angles


Lesson objectives


  1. Measure with a protractor
  2. Recap – Draw lines and angles accurately
  3. Introduce angles
  4. Recap – Angles on a straight line
  5. Recap – Angles around a point
  6. Calculate angles
  7. Vertically opposite angles
  8. Angles in a triangle
  9. Angles in a triangle – special cases
  10. Angles in a triangle – missing angles
  11. Angles in a special quadrilaterals
  12. Angles in regular polygons
  13. Draw shapes accurately
  14. Draw nets of 3-D shapes


What we want children to know


  • Know that there are 360 degrees in a full turn
  • Pupils draw shapes and nets accurately, using measuring tools and conventional markings and labels for lines and angles
  • Pupils describe the properties of shapes and explain how unknown angles and lengths can be derived from known measurements.
  • Know when they should measure an angle and when they should calculate the size of an angle from given facts
  • Recognise that vertically opposite angles share a vertex
  • Recognise that a net is a two-dimensional figure that can be folded to create a three-dimensional shape



What skills we want children to develop

Use knowledge to solve reasoning and problem solving questions such as:


What’s the same, what’s different?

  • What is the same and what is different about the nets of a triangular prism and a square-based pyramid?


Other possibilities

  • If one angle of an isosceles triangle is 36 degrees. What could the triangle look like – draw it. Are there other possibilities? Draw a net for a cuboid that has a volume of 24 cm3.


Always, sometimes, never


  • Is it always, sometimes or never true that, in a polyhedron, the number of vertices plus the number of faces equals the number of edges?



Vocabulary/Mathematical Talk


  • How can we find the missing angles?
  • What do the three interior angles add up to? Would this work for all triangles?
  • Does the type of triangle change anything?
  • If you know one angle is an isosceles triangle, what else do you know?
  • Is a square a rhombus? Is a rhombus a square?
  • What is a regular polygon? What is an irregular polygon?
  • How can we ensure our measurements are accurate?