Angles 2 and 5 are vertical angles.
Angles 4 and 6 are neither.
Angles 3 and 4 are adjacent angles.
Angles 1 and 4 are vertical angles.
∠2 and ∠5 are vertical angles because they share only a vertex.
∠3 and ∠4 are adjacent angles because they share a side and a vertex.
∠1 and ∠4 are vertical angles because they share only a vertex.
