# Perpendicular Vectors

Level pending

If $$x$$, $$y$$ and $$z$$ are real numbers such that the three vectors $\overrightarrow{a} = (x, 2, -4), \overrightarrow{b} = (1, y, 3), \overrightarrow{c} = (1, -2, z)$ are pairwise perpendicular to each other, what is $$x+y+z$$?

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