To simplify the first expression, we need to find a common denominator for the fractions in the denominator:

(1-4/9) / (1/3-1/4)
= (9/9 - 4/9) / (4/12 - 3/12)
= (5/9) / (1/12)
= (5/9) * (12/1)
= 60 / 9
= 20/3
= 6 2/3

Next, let's simplify the second expression:

(5/7 - 2/3) / (4/9 - 5/12)
= ((60/84) - (56/84)) / ((48/108) - (45/108))
= (4/84) / (3/108)
= (4/84) * (108/3)
= 432/252
= 2 3/14

Therefore, (1-4/9)/(1/3-1/4) : (5/7-2/3)/(4/9-5/12) = 6 2/3 : 2 3/14