Copyright © University of Cambridge. All rights reserved.

## 'Triangle Animals' printed from http://nrich.maths.org/

Grace and Brittany from Stradbroke Primary
both made the problem simpler to start with (this is often a good
way of starting a problem, so good thinking!). Grace wrote:

$1$ triangle makes $1$ shape

$2$ triangles makes $1$ shape

$3$ triangles makes $1$ shape

$4$ triangles makes $3$ shapes

It was hard to spot the ones that were
the same. I drew them on a piece of paper to make it easier to
check them.

Jonathan from Brick
Street Public School explained how he found the three different
ways for 4 triangles, starting with the shape made from
three triangles:

There are five sides to put the fourth
triangle in, but there are only three different sides to put the
fourth triangle in because two sides make the same shape.

Here is a picture of the
three shapes that Jonathan sent: