This corridor is one of the many corridors in Hogwarts Castle. It is located on the Grand Staircase side of the castle on the seventh floor circulates The Quad.
This wing has hundreds of bookshelves lined along the walls and various tables and furniture placed around the room. It serves the Castle as a reading room and study hall.
The Arithmancy Classroom is where Arithmancy classes are taught at Hogwarts School of Witchcraft and Wizardry. It's located on the seventh floor of Hogwarts Castle. It includes number charts, a blackboard and large rows of tables for students to sit in.
The Room of Requirement is a secret room in Hogwarts that only appears when a person is in great need of it. The room then transforms itself into whatever the witch or wizard needs it to be at that moment. It is believed that the room is unplottable.