Why do this
would be perfect to give to a very high-attaining
pupil. It offers a starting point that can lead to a hugh
variety of avenues to pursue.
Present the pupil with a kitchen roll (or similar) tube and
introduce the activity as suggested. If the learner is not
accustomed to exploring mathematically, you might consider
encouraging them to look at all the angles involved (both of the
required shape and the pieces cut off the $A4$). If s/he still
needs more prompting then you might consider suggesting they
explore these angles further.
There are further suggestions in the hints
Tell me what you have so far.
Which direction do you want to go in now?