Step 7 Objective

Classify quadrilaterals by their geometric properties.

Examples of what pupils should know and be able to do

Probing questions

What properties do you need to know about a quadrilateral to be sure it is a kite; a parallelogram; a rhombus; an isosceles trapezium?

How could you convince me that a rhombus is a parallelogram but a parallelogram is not necessarily a rhombus?

Why can't a trapezium have three acute angles?

Which quadrilateral with one line of symmetry has three acute angles?

What if pupils find this a barrier?

Use discussion activities, for example Always, sometimes, never true. Give pupils statements to explore and agree on whether they are always, sometimes or never true, for example:

For the above and other strategies see TMM from L5: Shape and space pp. 12-14.