Age 7 to 11 Challenge Level:
Why do this problem?
This problem will challenge pupils' knowledge of the properties of quadrilaterals. It is a good context for ''proof by exhaustion''
It might be useful to have some plastic quadrilaterals available so that the children can refer to them during the task. Children should be encouraged to "prove by exhaustion" that they have found all possible shapes.
This problem could be extended into compiling minimum sets of criteria to distinguish different quadrilaterals from each other. For example:
a rhombus and a kite
a rhombus, a kite and a square
a rhombus, a kite, a square and a rectangle.