Lengths of three measuring rods = 64 cm, 80 cm and 96 cm
Least Length of cloth that can be measured = LCM (64, 80, 96)

64 = 26
80 = 23 × 3 × 5
96 = 25 × 3
So, 26 × 3 × 5 are the greatest powers of the prime factors 2, 3 and 5
LCM (64, 80, 96) = 26 × 3 × 5 = 960
Least Length of cloth that can be measured is 960 cm