Find Greatest Common Divisor of 231 and 1575, using prime factorization.

Step 1 : Find prime factorization of each number.

$$\begin{aligned}231 =& 3\cdot7\cdot11\\[8pt]1575 =& 3\cdot3\cdot5\cdot5\cdot7\\[8pt]\end{aligned}$$

(view steps on how to factor 231 and 1575. )

Step 2 : Put a box around factors that are common for all numbers:

$$\begin{aligned}231 =& \color{blue}{\boxed{3}}\cdot\color{red}{\boxed{7}}\cdot11\\[8pt]1575 =& \color{blue}{\boxed{3}}\cdot3\cdot5\cdot5\cdot\color{red}{\boxed{7}}\\[8pt]\end{aligned}$$

Step 3 : Multiply the boxed numbers together:

$$ GCD = 3\cdot7 = 21 $$

This solution can be visualized using a Venn diagram.

The GCD equals the product of the numbers at the intersection.

GCD Calculator