The GCD of given numbers is 46.
Step 1 : Find prime factorization of each number.
$$\begin{aligned}2806 =& 2\cdot23\cdot61\\[8pt]1702 =& 2\cdot23\cdot37\\[8pt]\end{aligned}$$(view steps on how to factor 2806 and 1702. )
Step 2 : Put a box around factors that are common for all numbers:
$$\begin{aligned}2806 =& \color{blue}{\boxed{2}}\cdot\color{red}{\boxed{23}}\cdot61\\[8pt]1702 =& \color{blue}{\boxed{2}}\cdot\color{red}{\boxed{23}}\cdot37\\[8pt]\end{aligned}$$Step 3 : Multiply the boxed numbers together:
$$ GCD = 2\cdot23 = 46 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.