dijawab dengan cara ya

840 = 2^3 × 3 × 5 × 7
1980 = 2^2 × 3^2 × 5 × 11
3300 = 2^2 × 3 × 5^2 × 11
1440 = 2^5 × 3^2 × 5

GCD = 2^2 × 3 × 5 = 4 × 3 × 5 = 60 cm

Number of pieces = (840 : 60) + (1980 : 60) + (3300 : 60) + (1440 : 60) = 14 + 33 + 55 + 24 = 47 + 79 = 126 pieces