## Friday, 4 May 2012

After the Triangles We Followed Up With Quadrilaterals

Question was - what shapes can you make using a pair of quadrilaterals? I was most interested in following up the comment from Ross Mannell (see "Playing With Triangles" post) who suggested that it is interesting to see if kids can make odd sided shapes from quadrilaterals.

So, we got the cardboard rectangles and the scissors out and had a play.

First reaction was - "No way. You can't make a 5 or 7 sided shape from a pair of quadrilaterals!"

But after a bit of thinking, here's what we came up with:

A Pentagon:

"Excuse me Mr Ferrington,
I think I've made a pentagon!"

A Hexagon:

A hexagon with nicely labelled sides

A Heptagon:

We explored the suggestion from Ross Mannell
to use parallelograms for this one

An Octagon:

One of the first we discovered

A 32-gon:

Just a bit of whimsy but support for the theory
that the total maximum possible sides
equals number of shapes x number of their sides

In the conversations with the kids I was careful to always say "quadrilaterals" and avoid leading their thinking in any particular direction by suggesting they stick with squares or rectangle.

Lots of fun in Year 4 this week.

#### 1 comment:

1. Hello again everyone,

I can see you came up with the same solution as me by using quadrilaterals to form a heptagon. I can see our minds work alike. :)

I think the solution in making a pentagon is brilliant. As quadrilaterals are any four-sided shapes we must be willing to think outside the square.

Sorry about the above pun but I just finished sending a comment to a school looking at puns. :)

I can see by the 32-gon, you have also looked at a formula for determining the maximum number of possible sides using quadrilaterals. Maths can be wonderful, especially when we discover shortcuts to speed up calculation.

Thanks for sharing another interesting post.

@RossMannell
Teacher, NSW, Australia

Any comments you would like to make?