Find the GCD of the given numbers by prime factorisation method:

(i) 24, 45

(ii) 180, 252, 324

(i) 24, 45

Prime factorisation of the given numbers are:

24 = 2 × 2 × 2 × 3

45 = 3 × 3 × 5

The only common prime factor is 3 (appearing once in each).

Hence, GCD of 24 and 45 = 3.

(ii) 180, 252, 324

Prime factorisation of the given numbers are:

180 = 2 × 2 × 3 × 3 × 5

252 = 2 × 2 × 3 × 3 × 7

324 = 2 × 2 × 3 × 3 × 3 × 3

The common prime factors are 2 (twice) and 3 (twice) in all three numbers.

Hence, GCD of 180, 252 and 324 = 2 × 2 × 3 × 3 = 36.