Given,
HCF of 2472, 1284 and a third number ‘n’ is 12.
Their LCM is 23 × 32 × 5 × 103 × 107
Prime factorisation of 2472 = 2 × 2 × 2 × 3 × 103 = 23 × 3 × 103
Prime factorisation of 1284 = 2 × 2 × 3 × 107 = 22 × 3 × 107
HCF (2472, 1284) = 2 × 2 × 3 = 22 × 3
Thus, n also has the factors 22 × 3
From the LCM of three numbers, the another factor as the missing element of other number, i.e., 3 × 5
Therefore,
n = 22 × 3 × 3 × 5
n = 180