## Sunday, 26 April 2015

### Properties of Diagonals of quadrilaterals.

Is it just me, or here in the UK did we stop teaching about the properties that the diagonals of different quadrilaterals have? My top set Year 7 can spot a square, rhombus, rectangle, kite, arrowhead, parallelogram, or trapezium. They know that a trapezium only has one pair of parallel sides, and to avoid pitfalls thinking parallelograms have lines of symmetry. But of one area they remain very ignorant, the properties of the diagonals of different quadrilaterals.

The activity linked here is designed to address that. It starts by getting pupils to focus on the different properties that diagonals can have, and which quadrilaterals have those particular properties. This can be done with pictures of the quadrilaterals for pupils to reference, or without if pupils can deal with it. This is followed by a richer activity with pupils having to try and write sentences that only identify a selection of quadrilaterals, which can be extension or differentiated starting point. I haven't tried this with my Year 7 yet, but I do think there is merit in this sort of exploration of diagonals.