Solution

153858

First name
William
School
Marston Montgomery Primary School
Country
Age
10

Firstly,I looked at the first card. I then continued to look at the other cards. I started to draw up a shape; I then realised that I couldn't use all the cards. The one I didn't use was the card that said "the shape is irregular." My shape was a rectangle with the length equalling six and the width equalling four. I know that there are many other solutions and this is only one of all of them.

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This is what my shape looks like.