If a diameter around a pie is 33 cm and there is four people how would YOU split it equally?
Half for me and the other half for the other three.
The diameter doesn't go around the pie, it goes across. The perimeter goes around.
Cut it into quarters....
I would measure the circumference around the pie with a tape measure and mark it at 4th intervals . Then I would cut from one mark to the other across the pie, then I would turn the pie and cut across to the remaining two marks.
I'd eat the extra pie myself, then divide the rest equally.