Let $a,$ $b,$ $c$ be nonzero real numbers.  Find the maximum angle between the vectors $\begin{pmatrix} a \\ b \\ c \end{pmatrix}$ and $\begin{pmatrix} b \\ c \\ a \end{pmatrix},$ in degrees.
Question:
Let $a,$ $b,$ $c$ be nonzero real numbers.  Find the maximum angle between the vectors $\begin{pmatrix} a \\ b \\ c \end{pmatrix}$ and $\begin{pmatrix} b \\ c \\ a \end{pmatrix},$ in degrees.
Answer:
Let's think step by step.

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120^\circ
Let $a,$ $b,$ $c$ be nonzero real numbers.  Find the maximum angle between the vectors $\begin{pmatrix} a \\ b \\ c \end{pmatrix}$ and $\begin{pmatrix} b \\ c \\ a \end{pmatrix},$ in degrees.
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