Euclid's division lemma:
Let a and b be any two positive integers.
Then there exists two unique whole numbers q such that
a = bq + r ,
Where 0 less or equal to zero r < b
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According to the problem given,
First find the HCF of 1620 and 1725
1725 = 1620 × 1 + 105
1620 = 105 × 15 + 45
105 = 45 × 2 + 15
45 = 15 × 3 + 0
HCF ( 1725 , 1620 ) = 15
Now we have to find HCF of 15 and 255
255 = 15 × 17 + 0
HCF ( 15 , 255 ) = 15
Therefore ,
HCF ( 1620 , 1725 , 255 ) = 15
I hope this will help you.