The least common denominator of 3/4, 4/5, and 2/3 is given by the least common multiple of the denominators of the fractions.
That is the least common multiples of 4, 5 and 3
Therefore, the lowest common multiple = 2 x 2 x 3 x 5 = 60
Hence the least common denominator of 3/4, 4/5, and 2/3 is 60