Question

The prime factorisation of $180$ is

• A. $4\times 9\times 5$
• B. $2\times 2\times 3\times 3\times 5$
• C. $4\times 3\times 3\times 5$
• D. $2\times 2\times 3\times 5\times 5$

Answer 1

The correct option is B $2\times 2\times 3\times 3\times 5$

By Ladder Method:


Divide 180 by 2: Quotient = 90 with zero remainder,
Divide 90 by 2: Quotient = 45 with zero remainder,
Divide 45 by 3: Quotient = 15 with zero remainder,
Divide 15 by 3: Quotient = 5 with zero remainder,
Divide 5 by 5: Quotient = 1 with zero remainder,
Then, prime factorization of $180=2\times 2\times 3\times 3\times 5$