Step 1 :
Divide $ 3094 $ by $ 819 $ and get the remainder

$$ 3094 : 819 = 3 \text{ ( remainder is } \color{blue}{ 637 } \text{ ) } $$

The remainder is positive ($ 637 > 0 $), so we will continue with division.

Step 2 :
Divide $ 819 $ by $ \color{blue}{ 637 } $ and get the remainder

$$ 819 : 637 = 1 \text{ ( remainder is } \color{blue}{ 182 } \text{ ) } $$

The remainder is still positive ($ 182 > 0 $), so we will continue with division.

Step 3 :
Divide $ 637 $ by $ \color{blue}{ 182 } $ and get the remainder

$$ 637 : 182 = 3 \text{ ( remainder is } \color{blue}{ 91 } \text{ ) } $$

The remainder is still positive ($ 91 > 0 $), so we will continue with division.

Step 4 :
Divide $ 182 $ by $ \color{blue}{ 91 } $ and get the remainder

$$ 182 : \color{blue}{ \boxed { 91 }} = 2 \text{ ( remainder is } \color{blue}{ 0 } \text{ ) } $$

The remainder is zero => GCD is the last divisor $ \color{blue}{ \boxed { 91 }} $.

This solution can be visualized using a Venn diagram.

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

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