Question

Hcf of 27 and 45 and 81 by using prime factorisation

Answer 1

27=3×3×3=3power3
45=2power2×3power2
81=3power4
HCF are the common element with least power
therefore,hcf=3square=9

Answer 2

Factors of 27=1,3,9,27

Factors of 45=1,3,5,9,15,45

Factors of 81=1,3,9,81

So,1,3,9 are factors of these three numbers and the greatest no. is 9

So,HCF is 9