Cutting Corners

I really feel that it is good every now and again, to have such an activity as this, whichis an open investigation. From my experience it will need to be introduced in some enthusiastic way that will capture the pupils' interest and imagination. The pupils' understanding of the properties of these isosceles triangles will no doubt be enhanced. With some pupils you may get into the whole idea of pythagoras and square numbers and square roots. The concept of area is often challenged in this investigation as our eyes seem to play tricks on us and we have to verify things in a more certain way.

You could make use of any triangles (plastic or cardboard) that you have in the classroom and with the pupils gathered around get them talking about how they could be joined.

Do you notice anything about the pattern/shape you've made?

Can you make other shapes with the triangles you've chosen to use?

Star with a different kind of triangle to halve.

It may be necessary to help those who lack confidence in manipulation to move and flip the riangles.