Extensions
Can one consider three sections such that the OUTER perimeter (a tasty extra thick icing perhaps) is the same for all three sections.
Can one consider three sections such that the TOTAL perimeter (a tasty extra thick icing perhaps) is the same for all three sections.
Of course dividing the circle into three equal cuts (120 degrees each) through the center gives each participant equal area AND equal perimeter. Are there other "nice" cuts which do this, e.g., can any of our cuts do this? can they be modified to do this?
One could also consider the problem of cutting the cake into say n (n > 3) equal pieces and prescribing some geometrical constraints.