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CEMC Gauss (Grade 7), 2026

Geometry Difficulty 1.2 Junior Find the answer Canada

If a square's side length is a whole number, measured in
centimetres, which of the following could be the perimeter of the
square?

Pick one

Solution

Suppose that each side of the square has length $n~\text{cm}$ , where $n$ is a whole number. Then the perimeter
of the square is $4\times n~\text{cm}$ . This means that the perimeter of the square in
centimetres is a multiple of $4$ . Of
the choices given, only $32~\text{cm}$ is a multiple of $4$ .

(We note that in this case, the square has side length $n=8~\text{cm}$ .)

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Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty) added by this project.