which angle number represents an angle vertical to $\\angle psl$?

$which angle number represents an angle vertical to $\\angle psl$?$

which angle number represents an angle vertical to $\angle psl$?

Vertical angles are opposite, non-adjacent angles formed by intersecting lines. $\angle PSL$ is formed by lines $IK$ and $MP$.

The angle opposite $\angle PSL$ is $\angle 1$, as they share vertex $S$ and are non-adjacent.

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