Copyright © University of Cambridge. All rights reserved.

## 'Transformations on a Pegboard' printed from http://nrich.maths.org/

We had a number of solutions from Wellesley Park Primary School. From Elizabeth we had;

My solution is for the triangle you would move the top peg so it's in line with the bottom right one then there you go.

Lillie sent in;

1)You start off with a 3x3 grid and you had to double it to make it 2x bigger you had to take the 2 pegs at the top and bottom of the right side and move them 2 gaps.

2) You have to start with a scalene triangle and change it to a right angle triangle you are only allowed to move 1 peg so you move the top peg and move it so it is in line with the bottom left peg.

3) You start off with the original shape and you count the gaps between each peg and on the bottom there was 2 gaps, and along the side there was 8 gaps you have to double each side and pull 8 gaps along the bottom and then do the same to the other side and you end up with the bottom being 4 and the sides being 8 but you dont have to double the bottom of the shape because you already have a side
that is 4 gaps long.

Then Briony sent in;

1} On the first one what I did was started off with a 3 by 3 grid and moved the top left dome to the bottom left and moved it 2 gaps onwards and then I looked at what I did and I made a triangle.

2} You start with the original shape which is the triangle shape. So what I did was counted the gaps of the bottom bit which was 2, then I counted the side once which was 4, so 2 times 2 is 4 so i done 2 times 4 which makes. I moved the bottom right so it makes 8 gaps, then I moved the top right 8 gaps and it gave me my answer.

Lucy, who is educated at home, sent in a very clear solution to this question. For the first part she wrote:

You move the top peg to the right by one space. If you cut a square from all four corners, you end up with a quarter of it. In the middle of the square you get four right angles.

I think there is at least one other way to get a right-angled triangle. Can you see how?

Lucy continued:

For the second problem you know that the new shape is going to have sides $4 \times 8$ because the sides are multiplied by $2$. One of the sides is already $4$ so you just move the two right pegs $6$ spaces to the right.

Very well described solutions Lucy, thank you, and well done the pupils from Wellesley.