Question

find LCM and HCF of 75 and 225

Answer 1

 hi friend
75=5X3x5=5²X3
225=5x5X3X3= 5²X3²
LCM= least common multiple= 5²x3²=25X9=225
HCF=highest common factor=3x5²=75
______________________________________________________________

Answer 2

Answer :

LCM

=> least common factor In this question 75 and 225 have

75 and 225  = 3 x 3 x 5 x 5

then common number = 5 and 3 then its multiple of number called Prime factorisation method

$\begin{array}{r | l} 3 & 75,225 \\ \cline{2-2} 3 & 25,75 \\ \cline{2-2} 5 & 25,25 \\ \cline{2-2} 5 & 5,5\\ \cline{2-2} & 1 \end{array}$

So common factor = 3 x 5 => 15 is LCM of 75 and 225

Now HCF

=> Highest common factor In this question highest common number is HCF like :

75 = 3 x 5 x 5

225 = 3 x 3 x 5 x 5

$\begin{array}{r | l} 3 & 75 \\ \cline{2-2} 5 & 25 \\ \cline{2-2} 5 & 5 \\ \cline{2-2} & 1 \end{array}$

$\begin{array}{r | l} 3& 225 \\ \cline{2-2} 3 &75 \\ \cline{2-2} 5 & 25 \\ \cline{2-2} 5& 5 \\ \cline{2-2} & 1 \end{array}$

so HCF = 3 x 5 x 5 => 75 is HCF of 75 and 225