When finding right-angles you can use the 3-4-5 rule, which is sometimes called Pythagoras's theorem.

1. Insert a peg at the point you wish to find the right-angle at.

2. Measure and mark the 4 m length.

3. Measure the 3 m length and mark out an arc.

4. Measure the 5 m length and mark out an arc.

5. The point at which the two arcs overlap is where your next peg should go.

6. This forms a right-angle (90°) between the 3 m and 4 m lengths.

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