The pi terms cancel out when you divide. This is due to the rule x/x = 1 where x is any number you want except x cannot be zero. So replace x with pi and we have pi/pi = 1
Therefore,
(3pi)/(2pi) = (3/2)*(pi/pi)
(3pi)/(2pi) = (3/2)*1 .... use the rule mentioned above
(3pi)/(2pi) = 3/2
we get a fraction or a ratio of two whole numbers, so this proves that the given expression is rational.
