Copy the following Calculate the HCF of A. 300, 450 and 780

For 300:
$300 = 2 \times 150$
$150 = 2 \times 75$
$75 = 3 \times 25$
$25 = 5 \times 5$
So, $300 = 2^2 \times 3 \times 5^2$.

For 450:
$450 = 2 \times 225$
$225 = 3 \times 75$
$75 = 3 \times 25$
$25 = 5 \times 5$
So, $450 = 2 \times 3^2 \times 5^2$.

For 780:
$780 = 2 \times 390$
$390 = 2 \times 195$
$195 = 3 \times 65$
$65 = 5 \times 13$
So, $780 = 2^2 \times 3 \times 5 \times 13$.

The common prime factors are 2, 3, and 5.
The lowest power of 2 that appears in all factorizations is $2^1$.
The lowest power of 3 that appears in all factorizations is $3^1$.
The lowest power of 5 that appears in all factorizations is $5^1$.

HCF = $2^1 \times 3^1 \times 5^1 = 2 \times 3 \times 5 = 30$.

The HCF of 300, 450, and 780 is 30.