I was doing part (iii). For the first part of that questions,
$ D_{10} = \{e, \rho, \rho^2, \rho^2, \rho^4, \sigma\rho, \sigma\rho^2, \sigma\rho^3, \sigma\rho^4 \} $ where $\rho = (1 \ 2 \ 3 \ 4 \ 5) = (1 \ 2)(1 \ 3)(1 \ 4)(1 \ 5)$ and $\sigma = (2 \ 5)(3 \ 4)$ So since both of them are even, every elements in the set are even.
But then for the second part, does the labelling of the vertices matter? Surely they will be exactly the same and it will still be even? The shape remains the same. Is my reasoning correct or am I misunderstanding something?
Thanks in advance.