jmc

After identifying a factor of 2 in 9118 and 33,182, we find that the given integers appear to be difficult to prime factorize. Therefore, we turn to the Euclidean algorithm. To use the Euclidean algorithm to find the greatest common divisor of a set of three numbers, we first note that $\text{gcd}(a,b,c)=\text{gcd}(\text{gcd}(a,b),c)$ for integers $a$, $b$, and $c$. One way to see this is to consider the prime factorization of $a$, $b$, and $c$. Now we apply the Euclidean algorithm to the first pair of numbers to find $$\begin{array}{rl}\text{gcd}(9118,12,173)& =\text{gcd}(9118,12,173-9118)\\ & =\text{gcd}(9118,3055).\end{array}$$We could continue to apply the Euclidean algorithm as usual, but instead we note that $\text{gcd}(9118,3055)=\text{gcd}(9118,3055÷5)$, since 9118 is not divisible by 5. We find $$\begin{array}{rl}\text{gcd}(9118,12,173)& =\text{gcd}(9118,3055÷5)\\ & =\text{gcd}(9118,611)\\ & =\text{gcd}(611,9118-611\times 15)\\ & =\text{gcd}(611,-47)\\ & =47,\end{array}$$since long division shows that 611 is divisible by 47. Note that we chose 15 as the number of 611's to subtract from 9118 by dividing 9118 by 611 and rounding up to the nearest integer. Finally, we verify that 33,182 is divisible by 47. Altogether, we have $$\begin{array}{rl}\text{gcd}(9118,12,173,33,182)& =\text{gcd}(\text{gcd}(9118,12,173),33,182)\\ & =\text{gcd}(47,33,182)\\ & =\boxed{47}.\end{array}$$