Question

The highest common factor (HCF) of 72, 108 and 180 is

• A. 18
• B. 36
• C. 24
• D. 12

Hint:

Use the lowest power of each shared prime factor across all three numbers.

Answer 1

The Correct Option is B

Step 1: HCF of the first two.
$\mathrm{HCF}(72,108)=36$.
Step 2: Bring in the third.
$\mathrm{HCF}(36,180)=36$ since $180=36\times5$.
\[\boxed{36}\]