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2021 AMC 12D Question 16

AMC12 · 2021 AMC 12D

Question 16

Suppose $a,$ $b,$ $c$ are positive integers such that $$
a + b + c = 23
$$ and $$
\begin{aligned} &\gcd(a, b) + \gcd(b, c) \\ &\quad {}+ \gcd(c, a) = 9. \end{aligned}
$$ What is the sum of all possible distinct values of $a^2 + b^2 + c^2?$
  1. $259$
  2. $438$
  3. $516$
  4. $625$
  5. $687$