The measure of the angle between the lines $x = k - 1, y = 2k + 1, z = 2k + 3, k \in \mathbb{R}$ and $\frac{x+1}{2} = \frac{y-2}{1} = \frac{z-1}{2}$ is
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Always convert parametric line equations into symmetric (Cartesian) form to reliably read off the direction ratios from the denominators. Ensure the coefficients of $x, y, z$ in the numerators are all $1$ before reading the denominators.