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Brenda is walking round an irregular hexagon (a shape with six straight sides). She starts off part of the way along one of the sides.
At each vertex (corner) she turns.
How much does she turn in total when she has walked all the way round?
Use this example to prove that the sum of the external angles of any hexagon is $360$ degrees.
The external angle is found by extending the side and measuring the angle between the extended line and the next side.