The GCD of given numbers is 21.
Step 1 : Find prime factorization of each number.
$$\begin{aligned}1176 =& 2\cdot2\cdot2\cdot3\cdot7\cdot7\\[8pt]483 =& 3\cdot7\cdot23\\[8pt]\end{aligned}$$(view steps on how to factor 1176 and 483. )
Step 2 : Put a box around factors that are common for all numbers:
$$\begin{aligned}1176 =& 2\cdot2\cdot2\cdot\color{blue}{\boxed{3}}\cdot\color{red}{\boxed{7}}\cdot7\\[8pt]483 =& \color{blue}{\boxed{3}}\cdot\color{red}{\boxed{7}}\cdot23\\[8pt]\end{aligned}$$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.