Question 130333
the total length of the paper is 2880cm, 240*12cm


the mean, average, diameter is 7.5cm, (11cm+4cm)/2


so the paper will wrap around 2880/(7.5*pi) times __ this is the number of turns


the thickness of the paper is the thickness of the roll, (11cm-4cm)/2, divided by the number of turns
__ 3.5cm/(2880/(7.5*pi))